Showing papers on "BALB/c published in 1981"

Monoclonal vs. heterogeneous anti-H-8 antibodies in the analysis of the anti-phosphorylcholine response in BALB/c mice.

Abstract: Biological activities of monoclonal A/J antibodies to the T15 idiotype in BALB/c mice were compared to heterogeneous antibodies raised by conventional immunization procedures. Two monoclonal antibodies, AB1-2 and GB4-10, which are of the gamma 1, chi class, appeared to have identical specificities by binding criteria and reacted similarly to conventional antibodies in their abilities to induce neonatal suppression, inhibit plaque-forming cell induction by phosphorylcholine (PC) antigens and to inhibit specifically, anti-PC plaque-forming cells. However, in functional analyses of anti-PC responses in various strains of mice, discrepancies were noted in the T15 responses as defined by monoclonal antibodies and conventional antisera. This heterogeneity was also observed in adult mice suppressed with the GB4-10 monoclonal antibody. These animals eventually produced an anti-PC responses of AB1-2 idiotype but lacking the GB4-10 marker. These results show that the T15 IgM anti-PC response in BALB/c and other strains of mice is heterogeneous and probably consists of a family of clones. Particular clones can be precisely eliminated by the use of appropriate monoclonal antibodies, and the anti-PC response that eventually recovers is still T15+ but lacking the suppressed clones.

Comparison of two-stage epidermal carcinogenesis initiated by 7,12-dimethylbenz(a)anthracene or N-methyl-N'-nitro-N-nitrosoguanidine in newborn and adult SENCAR and BALB/c mice.

Abstract: In order to define factors which determine susceptibility to chemical carcinogenesis, mice sensitive (SENCAR) and resistant (BALB/c) to epidermal carcinogenesis were studied under several treatment conditions for sensitivity to initiation by 7,12-dimethylbenz(a)anthracene or N -methyl- N ′-nitro- N -nitrosoguanidine and promotion by 12- O -tetradecanoylphorbol-13-acetate. In newborns of both strains, topical application of initiator was much less effective than in adults. However, initiation by i.p. injection of 7,12-dimethylbenz(a)anthracene is at least as effective in newborns as in adults, which may indicate that topically applied carcinogen is not delivered effectively to target cells in newborns. Thus, newborn epidermis can respond to 7,12-dimethylbenz(a)anthracene as well as adult epidermis when the initiator is appropriately administered. SENCAR mice are much more sensitive than are BALB/c mice to both initiators, which suggests that enhanced metabolic activation of hydrocarbon carcinogens by SENCAR mice is unlikely to account for their sensitivity. Newborn male SENCAR's developed approximately 50% more papillomas than did females in all groups. BALB/c newborn mice developed so few tumors that a meaningful comparison of sensitivity of males and females could not be made. Thus, the increased sensitivity of SENCAR's was apparent regardless of route of administration of initiator or the age or sex of the mice. SENCAR mice also developed a significant number of papillomas and squamous cell carcinomas with 12- O -tetradecanoylphorbol-13-acetate promotion in the absence of an exogenous initiator. Therefore, the skin of SENCAR mice may contain an initiated population of cells capable of responding to tumor promoters.

Resistance and abrogation of resistance to cutaneous leishmaniasis in reconstituted BALB/c nude mice.

Abstract: RESISTANCE AND ABROGATION OF RESISTANCE TO CUTANEOUS LEISHMANIASIS IN RECONSTITUTED BALB/c NUDE MICE

Experimental cutaneous leishmaniasis. I. Nonspecific immunodepression in BALB/c mice infected with Leishmania tropica.

Abstract: Leishmania tropica in BALB/c mice causes a fatal infection accompanied by the development of multiple metastatic lesions. Spleen cells from these mice were shown to have depressed proliferative responses to concanavalin A (Con A), phytohemagglutinin (PHA), and lipopolysaccharide (LPS). Coinciding with this immunodepression was the development of a cell population capable of suppressing normal spleen cell responses to Con A. This suppressor cell activity was first observed at 6 wk and was present throughout the remainder of the infection. At 12 wk the suppressor cells could be removed by Sephadex G-10 passage or carbonyl iron treatment; however, Sephadex G-10 passage could not reverse the suppression at 18 wk. Indomethacin, a prostaglandin synthetase inhibitor, was found to abrogate the activity of the adherent suppressor cell, suggesting that prostaglandin production may be involved in the immunosuppression seen in these mice. In addition, Sephadex G-10 passage and indomethacin were found to markedly augment spleen cell responses to leishmanial antigen, indicating that the adherent suppressor cell is capable of regulating specific immunologic responses.

Lambda chain expression at different stages of ontogeny in C57BL/6, BALB/c and SJL mice

Abstract: In C57BL/6 and BALB/c mice, 2–3% of immunoglobulin-positive cells express λ1 and 1–2% λ2 chains at the cell surface. These percentages are constant from the time around birth until adult age. The levels of λ1 chains in serum antibodies correspond closely to those in the B cell population in both mouse strains whereas in the case of λ2 chains, they are three times lower in serum antibodies than in the B cell population. In strain SJL, λ2-bearing B cells occur in similar frequencies as in BALB/c and C57BL/6, both in newborn and adult animals. However, the level of λ2-bearing immunoglobulins in the serum is 30 times below that expected on the basis of the cellular analysis and 10 times lower than in BALB/c and C57BL/6. B cells expressing λ1-like light chains were found in normal frequency in newborn SJL mice with a monoclonal rat anti-λ1 antibody. In adult animals such cells were present in a frequency 100 times below that characteristic for BALB/c and C57BL/6 mice. The concentration of immunoglobulin reactive with rat anti-λ1 antibody was 300 times lower in SJL than in BALB/c and C57BL/6 serum, in accord with previous data (W. Geckeler et al., J. Exp. Med. 1978. 148: 1122). The notion that in SJL mice a control mechanism specifically suppressess λ chain expression is further supported by an analysis of the early primary anti-(4-hydroxy-3-nitro-phenyl)acetyl (NP) response. We show that this response is initially dominated by antibody-forming cells secreting antibodies with λ1-like light chains. These cells rapidly disappear and appear to be selected against particulary in the IgG response. The monoclonal SJL anti-λ1 antibody Ls136 (M. Reth et al., Eur. J. Immunol. 1979. 9: 1004) does not stain any B cells in SJL mice, whereas it detects λ1-bearing cells in C57BL/6 and BALB/c animals in the expected frequency.

Fv-4: Gene Controlling Resistance to NB-Tropic Friend Murine Leukemia Virus. Distribution in Wild Mice, Introduction Into Genetic Background of BALB/c Mice, and Mapping of Chromosomes

Abstract: A gene controlling resistance to NB-tropic Friend murine leukemia virus (F-MuLV) was studied in wild mice. Mice of various subspecies were crossed with inbred BALB/c mice, and their F1 hybrids were tested for resistance to F-MuLV. Some mice of Mus musculus molossinus (Japan), M. musculus castaneus (Taiwan and the Philippines), and M. musculus urbanus (Sri Lanka) appeared to have a dominant resistance gene. A partially congenic strain, BALB/c-Fv-4wr (C4W), was established by the introduction of the gene Fv-4wr from a M. musculus molossinus into the genetic background of BALB/c mice. [(C4W X DBA/2) X C57BL/6-Fvs] crosses revealed that Fv-4wr is located on chromosome 12 with the gene order of Fv-4w-Pre-1-lgh-1, apparently at the same site as the Fv-4. The resistance of C4W mice was indistinguishable from the Fv-4-controlled resistance of FRG mice.

The development of Balb/c cells persistently infected with respiratory syncytial virus: presence of ribonucleoprotein on the cell surface.

Abstract: Balb/c mouse cells were persistently infected with RS virus. Continued passage of the virus produced in these Balb/c cells resulted in a 10-fold increase in the amount of infectious virus produced. Approximately 80% of the BCH4 cells expressed RNP and “spike” antigen intracellularly and associated with the cell surface.

High-frequency cotransfer of the transformed phenotype and a tumor-specific transplantation antigen by DNA from the 3-methylcholanthrene-induced Meth A sarcoma of BALB/c mice

Abstract: We transformed BALB/3T3 mouse cells with cellular DNA extracted from the Meth A sarcoma, a 3-methylcholanthrene-induced tumor of BALB/c mice, and asked whether foci arising in the transfection possess the previously defined Meth A tumor-specific transplantation antigen (TSTA). Five of eight foci selected from one experiment possessed Meth A TSTA. DNA extracted from one of the five TSTA-positive clones was used in secondary rounds of transfection transformation. Four out of five foci tested from the secondary transfections possessed Meth A TSTA. These results suggest that in the Meth A sarcoma a transforming gene and a genetic determinant of TSTA are intimately related: they may be identical or very closely linked; alternatively, a particular transforming gene might induce the expression of a particular TSTA. Another possible explanation for these results is that the cotransfer of certain cellular genes by DNA transfection is considerably higher than predicted from the limited studies presently available.

Resistance to cutaneous leishmaniasis in genetically susceptible BALB/c mice.

Abstract: When injected cutaneously with promastigotes of an isolate of Leishmania tropica, BALB/c mice develop progressive cutaneous disease whereas lesions in BALB/c.H-2k mice heal after several weeks. Lesions in BALB/c mice injected into deep subcutaneous tissues with promastigotes are less obvious early but much more prominent later than in mice after strict intradermal injection. BALB/c mice injected with Corynebacterium parvum together with a preparation of frozen and thawed infected macrophages are more resistant to cutaneous disease than mice injected with either adjuvant or crude antigen mixture alone. Results of these experiments, and those on other mouse strains reported previously, will aid in the choice of mouse and injection regime to be used in testing the efficacy of isolated L. tropica antigens as vaccines.

Effect of neonatal castration on liver tumor induction by N-2-fluorenylacetamide in suckling BALB/c mice

Abstract: BALB/c mice were castrated at 2 days of age and control animals were sham-operated. Untreated male and female mice were also included for comparison. One-half of the mice in each group were fed on alternate days with 1.5% N-2-fluorenylacetamide suspended in 1% gelatine by stomach tube beginning at 1 week of age for a total of 14 feedings. The experiment was terminated when the mice reached one year old. Approximately 30% of the male mice, but none of the females, developed liver tumors in groups fed carcinogen. This male predominance in the incidence of hepatocellular carcinomas was completely abolished when the animals were castrated neonatally. No lesions were observed in the liver of mice treated with gelatine suspension alone except one with neoplastic nodule. Although it has been observed that liver tumors are produce more readily in younger than in older mice, the present investigation shows that male hormonal environment during early life is more important than the age on the development of liver tumors initiated by carcinogen.

Acquired immunity to Salmonella typhimurium and delayed (footpad) hypersensitivity in BALB/c mice.

Abstract: BALB/c mice are extremely susceptible to salmonella infections. Previous reports have suggested that this natural susceptibility is due to a defect in cell-mediated immunity (CMI) which correlates with their inability to develop a delayed (footpad) hypersensitivity reaction to a salmonella extract when immunized with attenuated salmonellae. We have shown that mice thus immunized are in fact highly resistant to superinfecting intravenous challenge with virulent organisms, at a time when the footpad test is still negative. The footpad test becomes positive 2-3 weeks later, after the appearance of CMI, which is already present at 1 week as measured by determining the fate of a superinfecting challenge in the RES. The positive footpad reactions that develop in BALB/c mice--and also in B10, and CBA and (B10XA/J)F1 mice--are transferable to normal recipients by thetasensitive spleen cells. However, although B10 mice give positive delayed hypersensitivity (DH) reactions, they are more susceptible to salmonellae of intermediate virulence than the DH negative BALB/c strain. We have also shown that previous reports which suggested that susceptible mice did not develop immunity when vaccinated with live organisms are probably due to the salmonella strain used for vaccination, which does not establish a carrier state. A strain which does establish a carrier state effectively immunizes the susceptible BALB/c strain against virulent challenge, indicating that natural susceptibility does not preclude the development of acquired immunity to reinfection. X

An abnormality of immune complex kinetics in murine lupus.

Abstract: In order to understand better the role of immune complex metabolism in the pathogenesis of autoimmune diseases, we have investigated the early stages of immune complex uptake by the liver, the major organ responsible for clearance of soluble complexes in the mouse. Livers were perfused in situ via the portal vein over 3 to 5 min with trace amounts of radiolabeled soluble model immune complexes. In 4 nonautoimmune strains (BALB/c, DBA/2, CAF1, NZW) 60 to 72% of the model complexes perfused were taken up and remained in the liver after 20 min of continuous perfusion with oxygenated Krebs-Henseleit buffer. In NZB and NZB/W F1 female mice at ages 0.5 to 11 mo, 66 to 78% of the model complexes remined in the liver. However, when a dose of heat-aggregated human gamma-globulin sufficient to saturate the reticuloendothelial system was perfused 7 min after radiolabeled complexes, 15.2 +/- 7.2% (mean +/- SD) of the complexes were displaced in the nonautoimmune strains. In contrast, 32.6 +/- 10.5% of the complexes were displaced from the liver in NZB and NZB/W F1 female mice (p < 0.001). Thus, although hepatic uptake of immune complexes in autoimmune mice appears to be normal or even enhanced, there may be impaired phagocytosis by the hepatic RES or weaker binding of complexes to the surface of the Kupffer cells. Such surface-bound immune complexes remaining accessible to the circulation may contribute to the autoimmune process.

Influence of Dietary Fat on the Growth of Mammary Ducts in BALB/c Mice

Abstract: Essential fatty acid (EFA)-deficient diets, when fed to weanling BALB/c mice, retarded the rate of mammary ductal growth. Ductal growth was also markedly retarded in pups fed only EFA-deficient foods from birth (milk from mothers fed EFA-deficient diets for the first 3 wk until weaning, then an EFA-deficient diet for an additional 5 wk). The ability of dissociated mammary epithelial cells to form outgrowths was reduced, and the growth rate of those outgrowths that did form was retarded when such cells were injected into gland-free mammary fat pads in syngeneic hosts fed EFA-deficient diets. Indomethacin, an inhibitor of prostaglandin synthesis, when added at a level of 0.003% to a 15% corn oil-containing diet, resulted in the retardation of ductal growth to about the same extent as did a 15% hydrogenated cottonseed oil-containing diet; however, unlike that associated with EFA-deficient diets, the retardation associated with indomethacin was temporary. EFA appears to be required for normal ductal growth in BALB/c mice, and prostaglandins may be involved in the growth-regulating process.

A study of immunoregulation of BALB/c mice by Echinococcus granulosus equinus during prolonged infection

Abstract: SUMMARY Two models of intraperitoneal infection with E. granulosus equinus by protoscolices and by cyst passage in BALB/c mice were used to provide mesenteric lymph node cells for adoptive cell transfer into syngeneic recipient normal responder mice. The cell transfer inocula were shown to have depleted Thy-1 cells, but to be highly suppressive to the normal sheep erythrocyte response of the recipients. The nature of the depletion and non-specific suppression, and the infectious nature of the latter, are discussed in relation to other examples of mitogenic stimulation resulting in non-specific T cell suppressor activity. The functions of Ly-2,3+ cells, not only as suppressor, but as alloreactive cytotoxic cells, are discussed as a possible, autoimmune explanation for the longevity of the parasite within the mouse model, in contradistinction to the predictable early rejection of analogous xenografts.

Mechanisms in T cell leukemogenesis. II. T cell responses of preleukemic BALB/c mice to Moloney leukemia virus antigens.

Abstract: The T cell responses of Moloney leukemia virus (MoLV)-infected preleukemic BALB/c mice were examined. The major in vitro response detectable was T cell blastogenesis in response to the major viral envelope protein MoLV gp71 and an internal viral protein p12. The majority of the preleukemic mice had readily detectable responses to gp71, whereas the presence of a response to p12 was less consistent. With both antigens, T cell blastogenesis showed typical antigen response characteristics similar to those detected in other immune responses to C-type viruses. Proliferation was dependent on a Thy-1+, Lyt-1+, 2- population and was macrophage-independent. In contrast to most immune responses to C-type viruses, which are temporally restricted, T cell blastogenesis was detectable throughout the preleukemic period of 4 to 16 wk of age. During this period neither gp71-specific T cells nor PHA-responsive T cells were found to express viral antigens. The correlations between T cells responding to gp71 and leukemia were examined. Under conditions in which MoLV inoculation of BALB/c mice does not induce leukemia, no T cell responses were deectable. These results suggest a causal relationship between the presence of antigen-specific T cells and the ability of MoLV to induce leukemia. The results are discussed with reference to the possible role of chronic immune stimulation in virus-induced leukemogenesis.

Studies on visceral Leishmania tropica infection in BALB/c mice. I. Clinical features and cellular changes.

Abstract: The visceral and lethal infection produced in BALB/c mice by Leishmania tropica (major) is accompanied by splenomegaly, anaemia and reversal of albumin-to-globulin ratio. The percentages of both B and T cells are decreased in the spleen. The spleen and lymph nodes become populated with large Ig-, Thy 1.2- 'null' cells. The similarity of some of these parameters with those produced in human kala-azar is discussed.

Relationship of idiotypes of the anti-p-azophenylarsonate antibodies of A/J and BALB/c mice.

Abstract: It has previously been shown that A/J anti-Ar antibodies contain 2 different families of cross-reactive idiotypes, referred to as the major and minor idiotypes populations. The present report shows that the minor A/J idiotype is related to a major idiotype of BALB/c anti-Ar antibodies. Anti-idiotype directed against the minor A/J idiotype binds 5 to 10% of A/J anti-Ar but an average of about 40% of BALB/c anti-Ar. This BALB/c population corresponds to the major BALB/c anti-Ar idiotype. For individual BALB/c anti-Ar preparations the maximum percentages of antibody bound by anti-id directed to A/J or BALB/c anti-Ar are very similar. Anti-id reactive with the minor A/J idiotypic population suppressed the formation of the BALB/c major idiotype when injected into BALB/c mice. Adsorption experiments showed that only about one-third of the minor A/J population is related to the BALB/c idiotype and that the expression of this idiotype is highly variable in individual A/J sera. Several types of evidence, obtained with hybridoma products expressing the major A/J idiotype, revealed no detectable relationship between the major A/J and BALB/c anti-Ar idiotypes.

An intrastrain cross-reactive idiotype associated with anti-p-azophenylarsonate antibodies of BALB/c mice.

Abstract: This paper describes an intrastrain cross-reactive idiotype, associated with the anti-Ar antibodies of all BALB/c mice tested. The idiotype is present on 20 to 65% of the anti-Ar antibodies of individual BALB/c mice and is localized to the Fab fragment. Adsorption of anti-Ar antibody from an immune serum completely removes the idiotypic activity. Inheritance of the idiotype is linked to the Igh locus, as shown by results obtained with congenic mice. It is present in strains that are Igh-Ia but not in the allotypically related Igh-Ij strains. The idiotype is also present in certain strains belonging to other allotype linkage groups. Expression of the idiotype is suppressed by the administration of rabbit antiidiotypic antibodies before immunization. The BALB/c idiotype is cross-reactive with an idiotype present in a small proportion of anti-Ar antibodies of A/J mice.

Membrane immunoglobulins of spontaneous B lymphomas of aged BALB/c mice

Abstract: Four cell lines derived from spontaneous BALB/c lymphoma tumors were analyzed with regard to the type of their membrane immunoglobulins (Ig) Using lactoperoxidase iodination of membrane proteins combined with immunoprecipitation and electrophoresis on polyacrylamide gel, three of these cell lines (X16c, L10A and K46) were found to express the monomeric form of IgM and IgD as well as half molecules One cell line (M12) lacked both IgM and IgD The apparent mol wt of the lymphoma micro chain was about 80 000 and exceeded the mol wt of 75 000 determined for micro chains secreted by myeloma cells The mol wt of the delta heavy chain was found to be 66 000 Immunofluorescence showed that the L10A and X16c lines expressed lambda light chains on their cell surface Another Ig-bearing cell line (K46) expressed both lambda and kappa chains Thus, three out of the four B lymphomas examined expressed both IgM and IgD with light chains of the Lambda type These results, together with our previous findings which demonstrate the presence of Ia and Fc receptors on the same cells, indicate that spontaneous B lymphomas in BALB/c mice are the malignant counterpart of mature B lymphocytes

Immune responses to labial infection of BALB/c mice with herpes simplex virus type 1.

Abstract: The kinetics of appearance of five humoral antibody responses (micro-neutralization assay [NT], complement fixation [CF], enzyme-linked immunosorbent assay [ELISA], radioimmunoassay [RIA], antibody-dependent cell-mediated cytotoxicity [ADCC]), were compared during labial infection of BALB/c mice with herpes simplex virus type 1 strain Patton. The ELISA/RIA antibody responses were present in most mice by day 5 after infection, at the beginning of the herpetic lip lesions; antibody effective in ADCC showed identical early kinetics. In contrast, NT/CF antibodies were not detected in most mice until day 10, at the time of resolution of the herpetic lip lesions. The humoral immune responses persisted for at least 6 months after infection. The NT and CF responses were closely correlated in time of appearance and titers (r = 0.9), as were the ELISA and RIA responses (r = 0.99). However, there was little correlation between NT/CF and ELISA/RIA responses (r = 0.02). The kinetics of the delayed type hypersensitivity response showed similar kinetics of appearance to the ELISA/RIA/ADCC humoral responses, and peaked similarly, but waned gradually over 2 months. The importance of antibody in protection against labial herpes simplex virus type 1 infection was demonstrated by the ability of passively transferred convalescent serum (that produced a minimum NT titer of 10 in recipient mice) to protect against development of herpetic lesions and death.

Differential DNA-repair activity in prespermiogenic cells of various mouse strains.

Abstract: The present report demonstrates differential DNA-repair activity among 14 strains of immature (20 ± 2 days old) male mice (inbred strains: C57BL/6J, RF/J, Nude homo/nu, RIII/2J, Pl/J, AKR/J, Nude hetro/nude, C3H/HeJ, SWR/J, SM/J, ST/J, LP/J, BALB/cJ and random-bred strain: CD-1). The prespermiogenic cells were isolated and enriched by collagenase-trypsin digestion of seminiferous tubules and subsequent 3% albumin-gradient centrifugation. Enriched prespermiogenic cells demonstrated a viabiilty greater than 95% by trypan blue exclusion criteria. For in vitro unscheduled DNA synthesis (UDS) determination, prespermiogenic cells (10 6 cells/ml) were incubated with methyl methanesulfonate (0.4 mM) in the presence of 20 mM hydroxyurea (HU). At 20 mM HU concentration, 90% of S-phase DNA activity in prespermiogenic cells was inhibited and thus, the net UDS activity following MMS exposure was readily determined. MMS-induced UDS activity in the CD-1 mouse strain was both linear up to 4 h of incubation and dose-dependent at 4 h incubation. The apparent K m for MMS-induced UDS activity in prespermiogenic cells was approx. 1.8 × 10 −4 M. Of the 14 mice strains tested, C57BL/6J and RF/J exhibited the highest DNA-repair activity, while BALB/cJ, LP/J, and ST/J showed the lowest. A maximal difference in UDS activity fo 3.5-fold was observed between C57BL/6J and BALB/cJ. Furthermore, a 2.5-fold difference was also noted between RF/J and LP/J mouse strains. Thus, wide variations in DNA-repair activity among 14 mouse strans were clearly demonstrated. Whether genetically select mouse strains with the lowest DNA-repair activity should have greater sensitivity toward environmental mutagens needs to be tested.

Partial Expression of Endogenous Mouse Mammary Tumor Virus in Mammary Tumors Induced in BALB/c Mice by Chemical, Hormonal, and Physical Agents

Abstract: The possible interaction of environmental factors with the endogenous mouse mammary tumor virus (MMTV) genome in the development of mammary tumors in the low-tumor-incidence BALB/c mouse strain was examined Tumors were induced in virgin female animals by treatment with chemical carcinogen 7,12- dimethylbenz[α]anthracene or urethan, with or without prolonged hormonal stimulation, or by X-irradiation Concomitant hormonal stimulation resulted in increased tumor incidences compared with those induced by chemical carcinogen treatment alone The frequency of tumor induction by irradiation alone or in combination with urethan or prolactin stimulation was very low MMTV expression in the mammary tumors was assayed by nucleic acid hybridization and by immunohistochemical staining Depending upon the treatment group, 0 to 89% of the tumors contained detectable levels of MMTV RNA (≥00005% of the total cellular RNA) Tumors which contained detectable viral transcripts exhibited only low levels of MMTV RNA, which did not appear to represent the accumulation of RNA sequences homologous to the entire MMTV genome; synthesis of MMTV structural proteins was detected in only one tumor Viral RNA-positive tumors were generally associated with a longer latent period MMTV RNA expression occurred in tumors classified histologically as adenoacanthomas, as well as in mammary adenocarcinomas, although the cell types in the adenoacanthomas expressing viral RNA were not identified It does not appear that expression of the endogenous MMTV genome is required for maintenance of all mammary tumors in BALB/c mice, although partial genome expression undetectable by the methods employed cannot be ruled out Linear regression analyses were performed The mean time to tumor appearance and the percentage of tumors which were MMTV RNA positive were found to vary linearly as a function of the total dose of 7,12-dimethylbenz[α]anthracene administered The percentage of tumors which were MMTV RNA positive was also shown to be linearly related to the mean time to tumor appearance These relationships provide a basis for predictions in the BALB/c system related to these parameters

Allelic forms of anti-phosphorylcholine antibodies.

Abstract: Anti-idiotype antisera were prepared to 2 phosphorylcholine (PC) binding myeloma proteins, T15 of BALB/c origin and C3 of C57BL origin. These antisera were shown to recognize the respective determinants on induced anti-PC antibodies in the 2 parental strains. Genetic analysis of these V region markers in backcross progeny of (BALB/c X C57BL/6) X BALB/c demonstrated that the 2 determinants segregated as simple Mendelian alleles linked to the allotype locus. The genetic data are consistent with previously reported structural studies suggesting the allelic nature of the T15 and C3 heavy chain variable regions. The expression of the T15 and C3 antigenic determinants in Ig congenic and recombinant inbred strains derived from BALB/c-C57BL/6 crosses further supports the concept of allelism although a single exception was observed. Strain distribution analysis has indicated the potential existence of other alleles of the T15 gene in addition to C3.

Genetic control of the immune response to the L-Glu60-L-Ala30-L-Tyr10 (GAT) terpolymer. V. Three types of idiotypic specificities on BALB/c anti-GAT antibodies.

Abstract: Three types of idiotypic specificities compose the major idiotype of anti-poly (L-Glu60-L-Ala30-L-Tyr10) (GAT) antibodies from BALB/c mice (idiotype termed GAT-715). Assays have been designed to analyzed and study the distribution of these specificities. The highly conserved idiotypic specificity (h.c.GAT) has been assayed by the binding of serum 715-7A4 to radiolabeled rat anti-GAT antibodies. Guinea pig and mouse anti-GAT antisera all express the same h.c.GAT specificity. The public specificity (p.GAT) has been shown to be present in an identical form in all anti-GAT antisera from all strains of mice studied. The assay used for p.GAT was the binding of serum 715-7A4 to C57BL/6 anti-GAT antibodies that express only p.GAT. Finally, the strain-restricted specificity s.r.GAT has also been investigated by radioimmunoassay; this specificity is expressed only by strains BALB/c, BALB/b, BUB/J, DBA/2, DBA/1 and ATL. This expression is independent of known allotypic markers. However, the expression of the s.r.GAT specificity of BALB/c mice follows the genetic distribution of VH genes of BALB/c origin indicating that s.r.GAT can be considered as a genetic marker of some VH gene(s) involved in the specific immune response to the GAT terpolymer.

Alteration of clonal profile II. Studies on the capacity of BALB/c splenic B cells to perpetuate responsiveness to phosphorylcholine and T15 idiotypic dominance

Abstract: (CBA/N x BALB/c)F1 hybrid male mice are unable to mount anti-phosphorylcholine (PC) plaque-forming cell (PFC) responses because they carry the CBA/N X-linked immune defect of B lymphocyte differentiation. Transplantation of splenic B cells from BALB/c mice restores responsiveness to thymus-dependent and thymus-independent PC antigens up to 8 months after cell transfer. Cytotoxicity studies demonstrate the donor origin of PFC generated in reconstituted (CBA/N x BALB/c)F1 mice. Although responsiveness to PC is restored permanently, a shift in idiotype expression that leads to the loss of T 15 idiotypic dominance 3 months after cell transfer can be detected. This shift originates from Ig- cells because Ig+ splenic cells purified in a fluorescence-activated cell sorter maintain T 15 dominance. Therefore, the Ig+ cells have a remarkable capacity to maintain responsiveness to antigens and can perpetuate idiotypic dominance if the stem cell pool is removed.

Clonal analysis of the BALB/c T cell proliferative response to apo beef cytochrome c.

Abstract: Murine T cell clones that proliferated specifically in response to the protein antigen apo cytochrome c were derived and maintained in continuous culture Two distinct clonotypes were observed with respect to the proliferative responses observed when a variety of peptides prepared from several species of cytochrome c were tested These 2 clonotypes appeared to recognize 2 different regions in the cytochrome c molecule Only 1 of the 2 clonotypes tested demonstrated helper cell activity for antibody formation in vitro