Showing papers in "Immunology and Cell Biology in 1979"
TL;DR: The data in this model system of cutaneous leishmaniasis raise the possibility that genetic susceptibility is associated with both a permissive macrophage and defective T cell recognition of parasite antigens on infected macrophages.
Abstract: The course of the disease, cutaneous leismaniasis, caused by the intracellular protozoan parasite Leishmania tropica, differs markedly amongst various common inbred mouse strains. After intradermal injection of 1 106 promastigotes to young female specific pathogen-free (SPF) derived mice, persistent infection characterized by an expanding ulcerous lesion is seen in BALB/c and DBA/2 mice. In the strains CBA/H, C3H/He and A/J, lesions resolve within 8 weeks, and in C57Bl/6 mice no real lesion typical of Cutaneous leishmaniasis develops at the injection site. NZB mice are highly resistant. Macrophages harvested from the thioglycollate-stimulated peritoneal cavity of NZB and C57Bl/6 mice appear to differ from macrophages of the other mouse strains in not supporting multiplication of L. tropica organisms in vitro. Nevertheless, hypothymic nude (nu/nu) mice of C57B1/6 genetype, as well as CBA/H-nu/nu and BALB/c-nu/nu mice, develop large lesions with metastases to other cutaneous and visceral locations. In the intact mice in which infection resolves spontaneously, resistance to reinfection is complete. Using mouse antipromastigote sera and an indirect fluorescent antibody test in carefully controlled experiments, L. tropica antigens were detected on in vitro infected macrophages of both highly susceptible BALB/c and relatively resistant CBA/H genotypes. After incubation with a crude soluble antigen preparation from cultured promastigotes, infected macrophages of both genotypes) in being unable to sensitize syngeneic recipients for a delayed-type hypersensitivity response to that antigen. When infected and uninfected macrophages were used as "blocking cell" in an in vitro alloreactive cytotoxic T cell system involving cells from congenic mice, evidence was obtained for reduced H-2d expression on infected macrophages of the susceptible mouse strain, BALB/c. The data in this model system of cutaneous leishmaniasis.
215 citations
TL;DR: D-beta-hydroxybutyrate inhibited the growth of rabbit kidney, HeLa, mouse melanoma, fibroblast and trypsin-dispersed human thyroid and beef testis cells, and in vivo dietary-induced ketosis reduced the number of B16 melanoma deposits in the lungs of C57BL/6 mice by two-thirds.
Abstract: The effect of ketone bodies on the growth, in culture, of transformed lymphoblasts (Raji cells) was investigated. Cell growth was inhibited and this effect was reversible, non-toxic, and proportional to the concentration of D-beta-hydroxybutyrate up to 20mM. The total glucose utilisation and the total lactate production were reduced in proportion to the inhibition of cell proliferation. D-beta-hydroxybutyrate was not metabolised by the cells. Other glycolytic inhibitors and chemical analogues of D-beta-hydroxybutyrate either did not inhibit or proved to be too toxic for cell growth. D-beta-hydroxybutyrate also inhibited the growth of rabbit kidney (RK13), HeLa, mouse melanoma (B16), fibroblast and trypsin-dispersed human thyroid and beef testis cells. Moreover, in vivo dietary-induced ketosis reduced the number of B16 melanoma deposits in the lungs of C57BL/6 mice by two-thirds. The significance of these results in the clinical management of cancer cachexia is discussed.
93 citations
TL;DR: Culex fatigans has in part replaced Culex annulirostris in peridomestic breeding sites at Kowanyama; the infrequency of virus isolation from it suggests that this replacement may lower arbovirus infection rates.
Abstract: 171,348 mosquitoes and 4,353 other arthropods collected at three centres in Queensland in 1972-1976 yielded 151 strains of 18 viruses. Culex annulirostris was the major source of virus isolation but 42 strains from Aedes normanensis indicate it to be a vector of importance. Ross River and Kokobera viruses were isolated at Kowanyama in the dry season, a finding of interest as being compatible with year-round survival in vector-vertebrate cycles. Culex fatigans has in part replaced Culex annulirostris in peridomestic breeding sites at Kowanyama; the infrequency of virus isolation from it suggests that this replacement may lower arbovirus infection rates. Twelve strains were identified as viruses antigenically distinct from any previously isolated in Australia or New Guinea: Ch16129, showed by the International Reference Centre for Arboviruses to be a previously undescribed member of the Simbu Group (Facey's Paddock virus), Ch16313 (Murweh), Ch19520 (Parker's Farm) and Ch19546 (little Sussex). The remaining strains were identified as viruses previously known in Australia, but included many new host or geographical records.
76 citations
TL;DR: Mice chronically infected with 3 metazoan and 1 protozoan parasite contain in their circulation levels of IgG1 which are increased over the levels in uninfected mice by at least 10x, and this apparently exaggerated response to chronic parasitic infection is of interest.
Abstract: Mice chronically infected with 3 metazoan and 1 protozoan parasite contain in their circulation levels of IgG1 which are increased over the levels in uninfected mice by at least 10x. In the case of infection with the larval cestode, Mesocestoides corti, the serum IgG1 concentration can reach greater than 50 mg/ml and, with a half-life of less than 2 days, the number of cells engaged in IgG1 production is approximately 2 x 10(8). The IgG1 hypergammaglobulinaemia is not seen in infected hypothymic nude mice. Biosynthetic labelling studies with organ and tissue cultures established that in two of the chronic infections the organs principally involved in IgG1 synthesis were those pathologically involved or those "in line" for antigen capture: i.e. liver and spleen in the case of M. corti which is located in the liver and the peritoneal cavity, and various intestinal lymph nodes in the case of the gut-dwelling nematode, Nematospiroides dubius. This apparently exaggerated response to chronic parasitic infection is of interest simply because of the potential magnitude of the effect and the fact that it involves an Ig isotype with very poorly defined biological function.
47 citations
TL;DR: Antigen dose response studies indicated that immune retention in lymph nodes occurred optimally with minute amounts of antigen, whereas optimal retention in the feet required much higher concentrations of antigen.
Abstract: Radioactive human serum albumin (125I-HSA) was injected into the hind foot pads of unimmunized mice, actively immunized mice and mice passively immunized with mouse or rabbit anti-HSA serum. Eleven days later the unimmunized mice had cleared most of the 125I-HSA. In contrast, a high concentration of 125I-HSA was retained in the feet and draining lymph nodes and, to a lesser extent, in the spleen of the actively or passively immunized mice. Although immune retention required specific antibody, it appeared to be independent of T-cells or T-cell factors, since passively immunized nude mice retained antigen as well as actively or passively immunized normal mice. Depletion of the complement system with cobra venom factor (CVF) increased antigen retention in the feet but decreased retention in the spleen. Treatment with CVF did not decrease antigen retention in lymph nodes of actively immunized mice. Such treatment did, however, decrease retention in lymph nodes of passively immunized mice although not to the same extent as in the spleen. Retention of antigen in the feet was not only complement-independent but was also Fc independent, since F(ab')2 fragments of IgG could mediate immune retention. Antigen dose response studies indicated that immune retention in lymph nodes occurred optimally with minute amounts of antigen, whereas optimal retention in the feet required much higher concentrations of antigen. Foot pad injections of non-radiolabelled HSA eliminated 60% of the radioactivity retained in the foot pads of immunized mice. In contrast, non-radioactive egg albumin (EA) had almost no effect on retained HSA. However, if the mice were immunized to both EA and HSA, an injection of EA would displace a significant amount of retained HSA. Complexes of one specificity can apparently displace some retained antigen of a differing specificity.
46 citations
TL;DR: In vitro lymphoproliferative responses to foreign histocompatibility antigens are phylogenetically restricted; responses occur most readily to allogeneic or closely related xenogeneic leucocytes, but not to unrelated Xenogeneic cells.
Abstract: In vitro lymphoproliferative responses to foreign histocompatibility antigens are phylogenetically restricted. Responses occur most readily to allogeneic or closely related xenogeneic leucocytes, but not to unrelated xenogeneic cells. Specific cytotoxic T cell responses to foreign histocompatibility antigens show the same phylogenetic restriction. This lack of xenoreactivity is not due to a lack of precursor cells for the xenoantigens; guinea-pig lymphocytes, although normally unresponsive to mouse antigens, have a similar precursor frequency for these antigens as do lymphocytes of allogeneic mouse strains. Specific cytotoxic responses of guinea-pig lymphocytes to mouse antigens can be generated if a factor released from con A stimulated guinea-pig spleen cells is added to the culture medium. The factor produced by con A-activated spleen cells (CS) is also phylogenetically restricted in its action; CS must be obtained from animals homologous with the donor of the responding lymphocytes.
32 citations
TL;DR: The results suggest that the extraordinarily high levels of IgG1 seen in the sera of mice chronically infected with the metazoa, M. corti and Nematospiroides dubius, reflect persistent, high-dose, "strong", T cell-dependent stimulation of the B cell system.
Abstract: IgG 1 HYPERGAMMAGLOBULINAEMIA IN CHRONIC PARASITIC INFECTIONS IN MICE: EVIDENCE THAT THE RESPONSE REFLECTS CHRONICITY OF ANTIGEN EXPOSURE
30 citations
TL;DR: Monoclonal antibodies derived from anti-parasite antibody-secreting hybridoma cell lines will be of particular use in the development of new, highly specific, immunodiagnostic reagents for the detection of parasite infection, exposure and disease.
Abstract: A prototype immunodiagnostic assay has been developed using chronic infection with the larval cestode, Mesocestoides corti, as a model system in mice. The assay is highly sensitive, it appears to be absolutely specific for M. corti infection, and is based on the inhibition of binding (by sera from infected mice) of a radiolabelled anti-M. corti hybridoma antibody to a crude M. corti antigen extract. The hybridoma antibody binds to living M. corti larvae and is an IgG1 protein. In large scale experiments no false positives were detected and the only M. corti-infected mice not detected by the assay were hypothymic nude (nu/nu) mice. Only limited success has been achieved in attempts to convert the assay to one not requiring parasite antigen and based on the inhibition of binding of radiolabelled anti-parasite hybridoma antibody and a large pool of anti-idiotype antiserum. Monoclonal antibodies derived from anti-parasite antibody-secreting hybridoma cell lines will be of particular use in the development of new, highly specific, immunodiagnostic reagents for the detection of parasite infection, exposure and disease.
27 citations
TL;DR: Results were taken to indicate that cattle do not readily acquire persistent T. gondii infections.
Abstract: During a four and a half year period a group of cattle was grazed continuously with a group of sheep and observed for Toxoplasma antibodies. Initially, there were 25 cattle and 31 sheep, but these were reduced to 19 and 18, respectively, by the end of the observation. Only transient antibody responses were noted in 2 cattle, whereas persistent titres developed in 12 sheep. Interpreted in the light of available information, these results were taken to indicate that cattle do not readily acquire persistent T. gondii infections.
24 citations
TL;DR: It is concluded, as has already been established for secretion of exportable protein, that alpha-adrenergic agonists have very similar effects to muscarinic agonists both on endpiece and on duct cells and that these actions are completely different from those evoked by activation of beta- adrenergic receptors.
Abstract: THE EFFECT OF PHENYLEPHRINE ON EXCRETION OF FLUID AND ELECTROLYTES BY THE PAROTID AND MANDIBULAR GLANDS OF THE RAT
23 citations
TL;DR: The results obtained from this study are in accord with the hypothesis that ryegrass staggers is caused by tremorgenic mycotoxins.
Abstract: PRODUCTION OF TREMORGENIC TOXINS BY PENICILLIUM JANTHINELLUM BIOURGE: A POSSIBLE AETIOLOGICAL FACTOR IN RYEGRASS STAGGERS
TL;DR: The supernatant from Con A-activated spleen cells (CS) can be used to generate homogenous populations of alloreactive T cells in vitro and is separable from the costimulator activity in CS required for the initiation of the T cell response to alloantigen.
Abstract: The supernatant from Con A-activated spleen cells (CS) can be used to generate homogenous populations of alloreactive T cells in vitro. Subculture of activated cells in CS containing medium is required for the continued proliferation and expression of effector activity. Prolonged subculture in CS containing medium does not result in indefinite growth and proliferation of alloreactive T cells. The activity in CS required to maintain cytotoxic cell growth is not species specific, and is therefore separable from the costimulator activity in CS required for the initiation of the T cell response to alloantigen; this latter activity is species specific.
TL;DR: A statistical association between focal interstitial nephritis and MA antibodies to hardjo was found in T. vulpecula, and the results confirmed the presence of leptospirosis in this population of possums.
Abstract: A serological survey for antibodies to Leptospira interrograns serovar hardjo was conducted on 574 serum samples from 10 native and 4 introduced wildlife species in south-eastern Australia. The microscopic agglutination (MA) test was used, and titres to hardjo antigen were detected in 33.5% of 352 brushtailed possums (Trichosurus vulpecula) sampled in several areas of Victoria. Prevalence of reactors ranged from 14 to 66% in 4 populations examined intensively. Serovar balcanica was isolated from possums with hardjo antibodies from two different areas. Of 20 wombats Vombatus ursinus) examined in Victoria, antibodies to hardjo were found in sera from 4 and titres to Pyrogenes and Pomona serogroups were detected in another. Hardjo antibodies were demonstrated in sera from 13 of 19 rusa deer (Cervus timorensis). Negative MA test results to hardjo antigens were recorded in 55 mountain possums (T. caninus), 63 macropods (Macropus spp.), 17 water rats (Hydrmys chrysogaster), 39 fallow deer (Dama dama), 2 hog deer (Axis porcinus) and 2 water buffalo (Bubalus bubalus). No MA antibodies to any of 16 leptospiral serogroups were detected in 17 water rats tested. Kidneys were examined from 330 of these animals and focal interstitial nephritis suggestive of leptospirosis was found in kidneys of 63 of 169 T. vulpecula, 3 of 55 T. caninus, 12 of 18 V. ursinus, 6 of 22 Macropus spp., 9 of 16 H. chrysogaster, 5 of 11 C. timorensis and 3 of 39 D. dama. A statistical association between focal interstitial nephritis and MA antibodies to hardjo was found in T. vulpecula.
TL;DR: In this paper, rotavirus RNA from calf, pig, mouse, deer, foal and dog-adapted human isolates was compared using polyacrylamide gel electrophoresis.
Abstract: Rotavirus RNA prepared from calf, pig, mouse, deer, foal and dog-adapted human isolates was compared using polyacrylamide gel electrophoresis. Reproducible differences in the RNA migration patterns were found between all isolates. There were 11 clearly resolved segments in the pig, mouse and foal samples. The calf rotavirus RNA and deer rotavirus RNA separated into 9 bands and 10 bands, respectively. The dog-adapted human virus migrated in 12 bands, and this probably results from the complex passage history of the original human rotavirus isolate.
TL;DR: Because Cx annulirostris activity continued throughout winter even at Charleville, continuous cycles of arbovirus transmission are possible, although the potential of dormant Aedes eggs also bears investigation as a method of arBovirus survival.
Abstract: SEASONAL ABUNDANCE OF CULEX ANNULIROSTRIS AND OTHER MOSQUITOES AT KOWANYAMA, NORTH QUEENSLAND, AND CHARLEVILLE, SOUTH WEST QUEENSLAND
TL;DR: The effects of major and minor trauma on the circulating white blood cell populations of C57BL mice were followed and it was shown that not only major trauma but minor injury and stress triggered a highly significant fall in the number of lymphocytes circulating in the blood.
Abstract: The effects of major and minor trauma on the circulating white blood cell populations of C57BL mice were followed. The results showed that not only major trauma (nephrectomy) but minor injury and stress (e.g. injection, bleeding) triggered a highly significant fall (50-70%) in the number of lymphocytes circulating in the blood. The fall was a gradual one, with the maximal drop 2 h after the operation or handling procedure. Major trauma resulted in a fall in both B and T lymphocytes. Minor trauma produced a fall in B lymphocytes only. A 3-4 fold increase in circulating polymorph numbers also accompanied major trauma, but no increase was observed after minor trauma. The blood picture returned to normal generally within 24 h of both minor and major trauma. Repetition of the trauma stimulus after recovery led to a renewed trauma response. Bilateral adrenalectomy abolished the lymphocyte response to major and minor trauma and decreased the polymorph response to major trauma by more than 50%, indicating that stress hormones played a role in these changes. Studies with 51chromium-labelled lymphocytes, transferred into traumatized and adrenalectomized animals, suggested that decreased entry of lymphocytes into the blood (rather than increased exit from the blood into the tissues, or cell death) was the most likely mechanism of the lymphopenia following trauma.
TL;DR: 51Cr-labelled uninfected cells, separated from Plasmodium berghei-infected mouse blood using the fluorescence-activated cell sorter, were cleared more rapidly than normal mouse erythrocytes after intravenous injection into normal mice.
Abstract: 51Cr-labelled uninfected cells, separated from Plasmodium berghei-infected mouse blood using the fluorescence-activated cell sorter, were cleared more rapidly than normal mouse erythrocytes after intravenous injection into normal mice.
TL;DR: Infection was maintained in possum populations by direct transmission, probably associated with breeding and agglutinin-absorption tests indicated that some possums may be infected with a leptospire more closely related to hardjo than to balcanica.
Abstract: The microscopic agglutination (MA) test was utilised to study the prevalence of antibodies to Leptospira interrogans serovar hardjo in 4 populations of brush-tailed possums (Trichosurus vulpecula). The overall antibody prevalence varied from 14% to 66%; however, the age distribution of MA test titres was remarkably similar in all 4 populations. Antibody prevalence was similar in both males and females and demonstrable antibodies were limited to sexually mature animals. The greater prevalence of high titres (greater than or equal to 1:128) in the 18- to 24-month age group suggested that primary infections were acquired at this age. The findings suggested that infection was maintained in possum populations by direct transmission, probably associated with breeding. Focal interstitial nephritis was observed in kidneys of possums greater than 18 months of age and was associated with MA titres to hardjo (P less than 0.001). Serovar balcanica was isolated from possum kidneys from 2 of these populations, suggesting that balcanica infections were responsible for most of the hardjo titres. However, agglutinin-absorption tests indicated that some possums may be infected with a leptospire more closely related to hardjo than to balcanica.
TL;DR: Investigation of beta-Glucosidase activity in tissues from a case of canine Gaucher disease and from a normal dog showed two pH optima at pH 4-0-4-25 and pH 5- 0-5-5.
Abstract: beta-Glucosidase activity was investigated in tissues from a case of canine Gaucher disease and from a normal dog. In the latter, enzyme activity showed two pH optima at pH 4-0-4-25 and pH 5-0-5-5. In Gaucher disease tissues, negligible activity could be measured at the mouse acidic pH.
TL;DR: There is a two-fold reduction in the number of H-2Kk molecules expressed on the surface of F1 cells, which is evident when F1 hybrid macrophages were compared with CBA/H and BALB/c macrophage as targets for both alloreactive and H- 2 restricted anti-viral TC cells.
Abstract: Sumniary. Cells of (CBA/H x BALB/c) Fi hybrid mice express CBA/H-derived H-2'' antigens more weakly than do CBA/H cells, but H-2'' antigens arc similarly exprcs.sed by Fl and BALB/c cells. This was evident when Fi hybrid macrophages were compared with CBA/H and BALB/c macrophage as targets for both allorcaclivc and H-2 restricted antiviral Tc cells. Quantitative absorption o f anti-H-2K^ serum by spleen cells of Fi or CBA/H mice also suggested about 3-fold less H-JK"* antigen on Fi cells. With the use of two anti-H-2K'' monoclonal antibodies. 3OR3 and 27R9. the reduced expression of H2K i n this Fi hybrid was further analysed in a two-stage radio-immunoassay employing the uptake ol'"M-protein \ t o measure antibody binding. By a thermodynamic approach, estimates were made ofthe dissociation constant for antibody binding, and of the relative numbers of H-2 molecules expressed by bolh Fi hybrid and CBA H spleen cells. The results indicate that there is a two-fold reduction i n the number of H-2K'' molecules expressed on the surface of Fi cells. Similar dissociation constants for Fi and CBA-'H ceils indicated no detectable qualitative difference in their H-2K'' antigens with respect to sites recc^nizedby3OR3and27R9.
TL;DR: The programme is specifically designed to generate best estimates of the limits and maximum slope of stimulus-response curves for the carotid sinus baroreceptor reflex, but is applicable to curve-fitting tasks in other fields such as immunology, pharmacology, biochemistry and neurophysiology.
Abstract: This paper describes a method, using an interactive computer programme, for fitting a curve to data which is expected to assume a sigmoid form The programme is specifically designed to generate best estimates of the limits and maximum slope of stimulus-response curves for the carotid sinus baroreceptor reflex, but is applicable to curve-fitting tasks in other fields such as immunology, pharmacology, biochemistry and neurophysiology
TL;DR: A small number of molecular species was detected in immunoprecipitates using host-protective sera which were apparently not quantitatively precipitated out of the complex mixture of labelled products of infected blood using sera from non-protected mice.
Abstract: In this methodological paper an immunoprecipitation technique has been optimised for the identification of antigens of Plasmodium berghei-infected blood which react with antibody specificities in a host-protective antiserum. Extracted 3H-leucine biosynthetically-labelled products of infected blood were sequentially reacted and precipitated with sera from mice which had been exposed to P. berghei but which were either non-protected or protected against lethal infection, protection having been shown to be transferable to naive recipients with the appropriate serum. As analysed by polyacrylamide gel electrophoresis under reducing conditions, a small number of molecular species was detected in immunoprecipitates using host-protective sera which were apparently not quantitatively precipitated out of the complex mixture of labelled products of infected blood using sera from non-protected mice.
TL;DR: Cholera immunization schedules were investigated in mice, with emphasis placed on obtaining an immune response in the intestine, and major differences between the immune responses in the spleen and the intestine were noted.
Abstract: Cholera immunization schedules were investigated in mice, with emphasis placed on obtaining an immune response in the intestine. The most effective schedule for producing a good local response was found to be several orally-given priming doses of the organism followed after 14 days by an intravenous boosting dose. Major differences between the immune responses in the spleen and the intestine were noted.
TL;DR: The cuticular surface of the infectious third-stage larvae of Nematospiroides dubius activates complement via the alternative pathway and the infectivity of larvae sensitized with antibody or complement was significantly reduced after incubation with cells from immune mice.
Abstract: The cuticular surface of the infectious third-stage larvae of Nematospiroides dubius activates complement via the alternative pathway. Sensitisation of larvae with complement or with antibodies from the serum of immune mice (resistant to reinfection) promoted the adherence of mouse peritoneal exudate cells to the larval cuticle during incubation in vitro. The infectivity of larvae sensitized with antibody or complement was significantly reduced after incubation with cells from immune mice.
TL;DR: It is indicated that, in this animal model, tissue levels of CCK probably do not modulate appetite and this study has failed to confirm the previous finding and indicates that the molecule may be a satiety factor.
Abstract: Cholecystokinin-(CCK) like peptides have been measured in the brain and small intestine of ob/ob hyperglycaemic mice and lean littermates. CCK-like peptides were measured by radioimmunoassay employing an antiserum to CCK octapeptide (CCK 8) and gastrin 17 I125 label. Although this antiserum detects gastrin with equal affinity to CCK, concomitant assay of tissue extracts with a gastrin specific antibody failed to reveal any detectable gastrin. Extracts of brain and small intestine showed levels of CCK of 96 +/- 12.6 pmol g-1 and 45 +/- 6.1 pmol g-1 in the obese mice; 101 +/- 8.7 pmol g-1 and 36 +/- 2.5 pmol g-1 in the lean mice. These were not significantly different. It has been suggested that CCK may be a satiety factor and it has been reported that there is less CCK in brain of obese mice compared with lean mice. This study has failed to confirm the previous finding and indicates that, in this animal model, tissue levels of CCK probably do not modulate appetite.
TL;DR: Studies were undertaken in adult groups aged 17-24 years, 25-64 years and 66-100 years to determine the haemagglutination-inhibiting antibody responses to sub-unit influenza containing A/USSR/90/77 (H1N1).
Abstract: Studies were undertaken in adult groups aged 17-24 years, 25-64 years and 66-100 years to determine the haemagglutination-inhibiting antibody responses to sub-unit influenza containing A/USSR/90/77 (H1N1). Antibody responses to A/USSR/90/77 were low in all groups. The young adult group (17-24 years) produced a primary response to A/USSR/90/77 and showed a significant response to a second dose of vaccine, whereas their responses to the A/Texas/1/77 (H3N2) and B/Hong Kong/8/73 components were of the anamnestic type and showed no significant increase to a second dose. The adult (25-64 years) and aged (66-100 years) groups responded anamnestically to all three vaccine components. There was no impairment of the antibody response in the aged group in comparison with the response in the adult group. A comparative assay in microtitre trays and WHO plates showed two- to four-fold differences in antibody titre to A/USSR/90/77 in these systems.
TL;DR: The extent of labelling internal cell proteins was measured by a procedure suitable for the comparison of a large number of samples: solubilized radioiodinated erythrocytes were electrophoresed on 14% acrylamide gels and the radioactivity determined in the haemoglobin band which migrates separately from other proteins.
Abstract: Optimal conditions were established for specific labelling of the surface proteins of mouse erythrocytes using lactoperoxidase-catalyzed radioiodination. The levels of H2O2 and I-, and cell concentrations required for restriction of haemoglobin labelling to less than 5% of the total 125I-protein, were different for radioiodination employing direct H2O2 addition or generation of H2O2 with glucose oxidase plus glucose. Preparation of mouse erythrocyte ghosts by hypotonic lysis caused loss of some minor labelled proteins present on intact cells and shifts to lower molecular weights of others. It is therefore important to solubilize labelled cells directly in electrophoresis buffer to avoid artifactual degradation of labelled proteins. The extent of labelling internal cell proteins was measured by a procedure suitable for the comparison of a large number of samples: solubilized radioiodinated erythrocytes were electrophoresed on 14% acrylamide gels and the radioactivity determined in the haemoglobin band which migrates separately from other proteins. The major labelled protein on the mouse erythrocytes had an apparent molecular weight of 92,000, and may be analogous to Band 3 of the human erythrocyte.
TL;DR: Results suggest that a methylating species is derived from DTIC but has a different reactivity toward DNA compared with MNNG, and patterns of DNA damage and repair similar to, but not identical with, those induced by the methylating agent MMNG.
Abstract: In seven human melanoma cell lines and one human fibroblast strain some correlation of resistance to cell killing was found with two bifunctional alkylating agents (melphalan, chlorambucil) and three monofunctional agents (4(5)-(3,3-dimethyl-l-triazeno)imidazole-5(4)-carboxamide (DTIC), methylmethane sulphonate (MMS) and N-methyl-N1-nitro-N-nitrosoguanidine (MNNG), but little cross-resistance was found between these two groups of agents or with cytosine arabinoside (ara-C) In contrast to previous studies with rodent tumours, potentially synergistic (chloroquine, arginine) or antagonistic (ascorbic acid, leucine) compounds did not affect the toxicity of melphalan in a human melanoma cell line In two melanoma lines DTIC induced patterns of DNA damage (inhibition of semi-conservative synthesis) and repair (strand breaks and repair synthesis) similar to, but not identical with, those induced by the methylating agent MMNG These results suggest that a methylating species is derived from DTIC but has a different reactivity toward DNA compared with MNNG
TL;DR: COA using THB cultures allows cheap and rapid screening for presumptive serotyping, having a 93-96% correlation with the CP test, and MID gives an accurate and unambiguous confirmatory diagnosis of serotype.
Abstract: Group B streptococci are implicated in a wide range of clinical conditions in human adults and neonates. The Group is subdivided into five serotypes Ia, Ib, Ic, II and III, which are differentiated on the basis of capsular polysaccharides. In the interests of epidemiology and efficiency a cheap, rapid method which is easily interpreted would be advantageous. In this study four methods of serotyping, namely, counter-immunoelectrophoresis (CIEP), microimmunodiffusion (MID), coagglutination (COA), and the Lancefield capillary precipitin (CP) test were compared in terms of ease of operation and interpretation, accuracy and rapidity. Todd Hewitt Broth (THB) cultures and acid extracts of the group B streptococcal strains were used as antigens for these methods. It was concluded that COA using THB cultures allows cheap and rapid screening for presumptive serotyping, having a 93-96% correlation with the CP test. MID gives an accurate (100% correlation with the CP test) and unambiguous confirmatory diagnosis of serotype.