Showing papers on "Cytotoxic T cell published in 1972"

The regulatory influence of activated T cells on B cell responses to antigen.

Abstract: Publisher Summary This chapter discusses the intimate mechanisms of the regulation of antibody responses by T cells, the significance of these phenomena for the regulatory processes of the immune system, and their possible implication for the pathogenesis of various immunopathological states. The chapter adheres to popular terminology to refer to the two distinct classes of immunocompetent lymphocytes—T cells and B cells. The T cells are lymphocytes that have differentiated under the influence of the thymus and are responsible for mediating cellular immune reactions—such as delayed hypersensitivity and transplantation reactions. These cells participate in the development of humoral immunity but are not capable of secreting humoral antibodies. Because T cells stimulated by antigen respond by a clonal expansion and differentiation; and by being activated to perform their specific function, the former is elected as “educated T cells” and the latter as “activated T cells.” Activated T cells may result from stimulation by agents other than specific antigen. The B cells are lymphocytes that have differentiated under the influence of the bursa or its analog in mammals and ultimately become the effector cells in humoral immunity by the virtue of synthesizing and secreting immunoglobulin antibodies.

A receptor for antibody on b lymphocytes : i. method of detection and functional significance

Abstract: Evidence is presented for the existence on all B lymphocytes, but not on T lymphocytes, of a membrane-associated receptor for antibody. The receptor was detected by a radioautographic technique in which lymphoid cells were incubated with antibody followed by the corresponding radioiodinated antigen. The ease with which antibody eluted during washing indicated that the bond between antibody and cell was weak. The formation of an antibody-antigen complex on the cell surface, however, stabilized the bond and permitted accurate quantitation of cells with adherent antibody. The ability of several combinations of antibody and antigen to adhere to the cells demonstrated the nonspecificity of the phenomenon and emphasized the need for care in interpretation of antigen-binding studies particularly when immune cells are being used. The identity of antibody-binding lymphocytes was established by two different approaches. In the first, mouse lymphocyte populations greatly enriched for either T cells or B cells were examined. Their T cell content was assessed by means of well-established markers such as the θ C3H isoantigen. When this was compared with the number of antibody-binding cells, an inverse relationship was obtained in each instance; thus almost all thoracic duct cells from athymic mice labeled with an immune complex although none were θ positive. The striking reduction in antibody-binding cells observed in bursectomized chickens provided a second and independent line of evidence suggesting that B cells, not T cells, bind antibody. The ability of B cells from primed animals to bind antibody in vivo made it important to test whether this phenomenon was related to the carriage of immunological memory. No correlation was, however, found between membrane-bound antibody and memory. It was proposed that the existence of a receptor of this kind may provide a rational explanation for antibody-dependent killing of target cells and may prove of importance in antigen concentration particularly during the secondary response.

Mechanism of Immunologically Specific Killing of Tumour Cells by Macrophages

Abstract: THE increase in anti-microbial activity of macrophages which occurs in animals that have been infected with living microorganisms is frequently non-specific1. In contrast, the anti-tumour activity of macrophages from immunized animals has been demonstrated in vitro to be immunologically specific2,3. The experiments to be described may throw light on this paradox. They show that the killing of tumour cells by macrophages is made up of an immunologically specific interaction which is followed by a non-specific lethal reaction. A similar pattern has been described for the bactericidal action of immune macrophages3. We have described three ways of obtaining immunologically specific macrophages cytotoxic to tumour cells3,5. These are (1) from the peritoneal cavity of suitably immunized mice (see later); (2) “arming” in vitro by contact of non-immune macrophages with spleen cells from hyperimmunized mice, and (3) “arming” in vitro by exposure of non-immune macrophages to the cell-free supernatant obtained when spleen cells from immunized mice are cultured with the specific antigen. All such macrophages, on coming into contact with specific antigens, undergo a transformation (referred to as “activation”) which renders them capable of killing. The actual destruction of the target cell following direct contact with the “activated” macrophages is non-specific. Moreover, this non-specific killing may also be demonstrated by macrophages “armed” against tubercle bacilli (BCG) which are “activated” after exposure to the solubilized protein derivative from tubercli bacilli, PPD, and are able to kill tumour cells. In the original experiments3,5 in which target lymphoma cells were added to “armed” macrophages the immunologically specific stage and the non-specific stage of the cytotoxic reactions were not separated and occurred sequentially (Fig. 1).

Serum mediated inhibition of the immunological reactions of the patient to his own tumour: a possible role for circulating antigen.

Abstract: In a microcytotoxicity assay the lymphocytes from cancer patients were tested on autologous and allogeneic tumour cells in vitro. In patients with a variety of tumours, extensive washing of the lymphocytes from those cases with advanced disease was found to greatly enhance their specific cytotoxic effects. This specificity was restricted to autologous tumour cells and allogeneic cells of similar histological origin. This cross-reacting cytotoxicity was not, however, universal, especially in cases of malignant melanoma. The cytotoxicity evoked by washing was abolished by the addition of the patient's serum. This serum effect showed a similar specificity to that found for lymphocyte cytolysis. The effect of washing, and the specific inhibitory effect of serum, was not detectable in early cases of primary malignant melanoma. The serum component responsible for inhibiting lymphocyte cytotoxicity had no detectable affinity for the target cells and appears to act on the lymphocyte surface, implying that tumour antigen may well be implicated.

Serologically defined and lymphocyte-defined components of the major histocompatibility complex in the mouse

Abstract: The mixed leukocyte culture (MLC) test is an in vitro model of the recognition phase of the homograft response. For the most part, activation in MLC is dependent on differences of the major histocompatibility complex (MHC). Our present studies in the mouse suggest that activation is primarily associated with differences of genetic regions of the MHC other than those which control the serologically defined (H-2) antigens. These differences do not lead to cytotoxic or agglutinating antibody formation despite extensive immunization; we have called these differences lymphocyte-defined (LD) differences. The strongest stimulation in MLC is associated with differences of the Ir region. It is possible that the Ir product is the T cell receptor and that it is this same molecule which can act as the stimulatory agent in MLC. Other possibilities are discussed.

Blocking of lymphocyte-mediated cytotoxicity for rat hepatoma cells by tumour-specific antigen-antibody complexes.

Abstract: LYMPHOCYTES from tumour-bearing animals are often cytotoxic in vitro against cultured tumour cells from the same individual1–4. It is possible that the serum of tumour-bearing hosts may contain circulating factors which interfere with the cell-mediated immune responses concerned in tumour rejection reactions5. Evidence has been provided by the demonstration that lymphocyte cytotoxicity against cultured tumour cells could be blocked by first exposing tumour cells to serum from tumour-bearing animals2,3; similar effects have also been observed in cancer patients6,7. The blocking factor in tumour-bearer serum has the characteristic properties of 7S immunoglobulins2, suggesting the involvement of tumour-specific antibody. Serum blocking activity is rapidly lost, however, in animals rendered tumour free and the activity of tumour-bearer serum can be neutralized by the addition of serum from these animals8,9. One explanation is that the blocking factor in tumour-bearer serum is antigen-antibody complex and the objective of these studies, using a transplanted rat hepatoma (D23), was to test directly whether such complexes prepared from solubilized tumour-specific antigen and antiserum exhibit blocking activity.

Cell interactions in the immune response in vitro. V. Specific collaboration via complexes of antigen and thymus-derived cell immunoglobulin.

Abstract: The mechanism of interaction of T and B lymphocytes was investigated in an in vitro hapten carrier system using culture chambers with two compartments separated by a cell impermeable nucleopore membrane. Because specific cell interaction occurred efficiently across this membrane, contact of T and B lymphocytes was not essential for cooperation which must have been mediated by a subcellular component or "factor." By using different lymphoid cell populations in the lower culture chamber and activated thymus cells in the upper chamber (with antigen present in both), it was found that the antigen-specific mediator acted indirectly on B cells, through the agency of macrophages. Macrophages which had been cultured in the presence of activated T cells and antigen acquired the capacity to specifically induce antibody responses in B cell-containing lymphoid populations. Trypsinization of these macrophages inhibited their capacity to induce immune responses, indicating that the mediator of cell cooperation is membrane bound. By using antisera to both the haptenic and carrier determinants of the antigen as blocking reagents, it was demonstrated that the whole antigen molecule was present on the surface of macrophages which had been exposed to activated T cells and antigen. Because specifically activated T cells were essential a component of the antigen-specific mediator must be derived from these cells. By using anti-immunoglobulin sera as inhibitors of the binding of the mediator to macrophages, the T cell component was indeed found to contain both κ- and µ-chains and was thus presumably a T cell-derived immunoglobulin. It was proposed that cell cooperation is mediated by complexes of T cell IgM and antigen, bound to the surface of macrophage-like cells, forming a lattice of appropriately spaced antigenic determinants. B cells become immunized by interacting with this surface. With this mechanism of cell cooperation, the actual pattern of antigen-B cell receptor interactions in immunization would be the same with both thymus-dependent and independent antigens. An essential feature of the proposed mechanism of cell cooperation is that macrophage-B cell interaction must occur at an early stage of the antibody response, a concept which is supported by many lines of evidence. Furthermore this mechanism of cell interaction can be elaborated to explain certain phenomena such as the highly immunogenic macrophage-bound antigen, antigenic competition, the distinction between immunity and tolerance in B lymphocytes, and the possible mediation of tolerance by T lymphocytes.

Control of Carcinogenesis: A Possible Role for the Activated Macrophage

Abstract: Cytotoxic activity of activated mouse macrophages against mouse embryo fibroblasts was tested before and after spontaneous transformation of the fibroblasts in vitro. Activated macrophages caused little or no destruction of untransformed fibroblasts but were markedly cytotoxic to the same fibroblasts after spontaneous transformation. The efferent limb of this cytotoxic reaction appears to be nonimmunologic and to be related to abnormal growth properties rather than to the antigenic composition of target cells.

Action of Camptothecin on Mammalian Cells in Culture

Abstract: Summary Camptothecin (CN) is active against several experimental tumors and has also been studied clinically. We report here the effect of CN on L1210 cells and asynchronous and synchronous DON cells in culture. CN was toxic both to L1210 cells (0.06 µg/ml, 2-hr exposure) and DON cells (0.15 µg/ml, 1-hr exposure), and it inhibited DNA and RNA synthesis more than it inhibited protein synthesis. CN was more cytotoxic to DON cells in S phase than cells in G1 or G2, although it inhibited DNA and RNA synthesis of L1210 cells and asynchronous DON cells almost equally. When asynchronous DON cells were exposed to CN for 30 min and CN was then removed, RNA synthesis was no longer significantly inhibited, but the inhibition of DNA synthesis persisted. The survival patterns of synchronous DON cells were closely related to DNA synthesis inhibition but not to RNA synthesis inhibition. These results collectively suggested that the marked effect of CN on DNA synthesis appeared to be one of the primary determinants of its cytotoxicity. Since no significant effect was observed on the enzymes involved in DNA synthesis, DNA synthesis inhibition by CN may be in part due to its effect on the DNA template. The interaction between CN and DNA was detected by melting point determinations. CN did not block the progression of mitotic cells into S phase. At 100 µg/ml, CN prevented the progression of S phase cells into G2; at 1 µg/ml, some cells did leave S and proceeded into G2. Cells in G2 were blocked from moving into mitosis even at 0.01-µg/ml doses of CN. Thus, the progression of late S or early G2 cells into mitosis was most sensitive to the drug.

Cell-mediated immune response in vitro. Iii. The requirement for macrophages in cytotoxic reactions against cell-bound and subcellular alloantigens.

Abstract: All efficient cell separation procedure and specific anti-macrophage serum were used to investigate the requirement of macrophages in the in vitro allograft response of mouse lymphoid cells. The efficiency of the macrophage-depletion procedure used and the undiminished capacity of the purified lymphocytes to respond were verified by also testing the antibody responses to sheep red cells (SRC) and dinitrophenylated polymeric flagellin (DNP POL) as well as the proliferative response to allogeneic cells. It was found that the generation of cytotoxic lymphocytes were diminished after macrophage depletion by surface adherence. The combination of anti-macrophage serum and column purification resulted in the total abolition of cytotoxic activity. The cell-mediated immune response was restored completely by addition of peritoneal macrophages, with as few as 1 macrophage to 600 lymphocytes permitting a significant restoration. Macrophages were not involved in the cytotoxic effector phase, but were essential in immune induction. A subcellular H-2 alloantigen preparation was only immunogenic in the presence of macrophages, indicating that a mere reduction in the size of the antigen from cell-bound alloantigens to membrane fragments was not the sole function of macrophages. The results suggest that macrophages collaborate with T cells in the initiation of an allograft response in vitro.

Cells mediating specific in vitro cytotoxicity. II. Probable autonomy of thymus-processed lymphocytes (T cells) for the killing of allogeneic target cells.

Abstract: In order to investigate whether only T cells are involved in a cell-mediated cytotoxic system in vitro, we tested the cytotoxicity of immune killing cell populations as deprived as possible of B cells. Educated thymus cells, immune spleen cells purified by filtration through a column of beads coated with antimouse Ig antiserum, and finally educated thymus cells further purified by filtration through such a column fully retained their specific cytotoxic activity. This very strongly suggests that only T cells are involved in the killing of target cells by allogeneic immune cells in vitro, in this system. Receptor-bearing cells involved in killing in the present system are thus very probably T cells. This point was further strengthened by the demonstration of specific adsorption, on the relevant monolayers, of each of the three above mentioned killing cell populations.

Cell Cycle Phase Specificity of Antitumor Agents

Abstract: Summary The sensitivity to drugs of synchronous and asynchronous populations of DON cells was studied. Agents that were cytotoxic at a specific phase of the cell cycle gave dose-survival curves that decreased to a constant saturation value. DNA synthesis inhibitors such as 1-β-d-arabinofuranosylcytosine, 5-azacytidine, 5-hydroxy-2-formylpyridinethiosemicarbazone (NSC 107392), sodium camptothecin (NSC 100880), 5-fluorodeoxyuridine, and pseudourea (NSC 56054) were most cytotoxic to cells in the S phase. However, the DNA synthesis inhibitor, neocarzinostatin, was most cytotoxic to cells in the G 1 phase. The protein synthesis inhibitors, pactamycin and sparsomycin, were also most cytotoxic to cells in the S phase. Cells in the G 1 -S border region were most sensitive to the RNA synthesis inhibitors, actinomycin D and nogalamycin, and to the alkylating agents, 1,3-bis(2-chloroethyl)-1-nitrosourea, and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. Streptozotocin and tubercidin, which markedly inhibit the synthesis of DNA, RNA, and protein, were cytotoxic to cells in all phase of the cell cycle. 5-Fluorouracil was also not phase specific. Cells in mitosis and in the G 1 phase were most sensitive to chlorambucil, l-phenylalanine mustard, and ellipticine.

The origin of alveolar macrophages in mouse radiation chimeras

Abstract: This investigation attempted to determine whether the primary source of alveolar macrophages is pulmonary or hematopoietic We have utilized an antigenic marker to identify cells of hematopoietic origin Mouse chimeras were produced by irradiating C57B6/AF1 mice (900 R) and then injecting them intravenously with B10D2/AF1 bone marrow The donor animal has an antigenic specificity on the H-2 locus, not shared by the recipient Alveolar macrophages were obtained by repeated lung washings with physiologic saline at 37°C Cytotoxic tests were done on bone marrow and alveolar macrophages using anti-31 mouse antibody, absorbed rabbit serum as complement, and trypan blue exclusion as a test for viability Animals were studied at 7, 14, 21, 28, and 35–50 days and 4, 5, 8, and 11 months after irradiation and bone marrow replacement By 21 days after irradiation, 90% of the animals had greater than 80% replacement of marrow with donor tissue; and white blood cell and alveolar macrophage counts approached normal At this time and at later intervals the per cent of donor cells in the lung free cell population was not significantly different from the per cent of donor cells in the bone marrow Similarly, after aerosol particulate exposure, the percentage of marrow cells and alveolar macrophages of donor origin were not significantly different This immunologic approach suggests that alveolar macrophages in radiation chimeras are entirely of hematopoietic origin

Cell surface immunoglobulin : iv. distribution among thymocytes, bone marrow cells, and their derived populations

Abstract: Thymocytes, bone marrow cells, and their derived T and B cell populations were examined for the presence of Ig by the cell surface radioiodination technique. Both IgM and IgG were identified on bone marrow cells. Thymocytes and T cells had no detectable cell surface Ig. Radiolabeling of mixtures of B cells and thymocytes suggest that the method may detect as little as 250 molecules of Ig per cell. Based on these findings, we suggest that the T cell receptor for antigen is not a conventional tetrameric Ig.

Lymphocyte cytotoxicity reactions to leukemia-associated antigens in identical twins.

Abstract: Cellular cytotoxicity reactions to human leukemia cells were measured with a sensitive, quantitative assay of cell-mediated immunity. Freshly explanted leukemia cells, rather than tissue culture cells, were tested to ensure that the antigens detected were not acquired in vitro. Identical twins, one member of each pair having leukemia, were used to minimize genetic variables and histocompatibility differences, thereby providing comparable normal cells to control for the leukemic cells. Leukemia-associated antigens were detected on the cells of seven of ten leukemic patients. In no instance was reactivity observed against only the cells of the normal twin. Lymphocytes from three identical twins, seven parents, two siblings and eight normal unrelated individuals were cytotoxic for cells from the leukemic patients but not for cells from these patients' normal identical twins. Lymphocytes from adults had a much higher incidence of reactivity (46%) against the leukemic cells than did the cells of children (9%). Positive lymphocyte cytotoxicity reactions to leukemia-associated antigens indicate previous sensitization which could have resulted from infection with an environmental agent such as a virus.

Thymus-derived lymphocytes produce an immunologically specific macrophagearming factor

Abstract: Spleen cells from mice immunized with an allogeneic tumor when cultured with the specific tumor cells release into the supernatant a specific macrophage-arming factor(s) (SMAF) which binds nonspecifically to macrophages from both mice and rats and renders these cytotoxic to the specific tumor cells. SMAF also binds in an immunologically specific way to the target cells. SMAF-treated target cells grow normally in the absence of macrophages but are killed in the presence of normal macrophages. Thymus-derived cells are necessary for the production of SMAF since (a) after treatment with anti-θ serum immune spleen cells fail to release SMAF; (b) spleen cells from immunized T cell-deprived mice (thymectomized as adults followed by whole body irradiation and restored with bone marrow) fail to produce SMAF on stimulation with the specific target cells. While SMAF has the properties of a cytophilic antibody, it does not belong to one of the established classes of immunoglobulin since high activity is found after column separation in a fraction having a molecular weight between 50,000–60,000 daltons.

Competition for receptors for immunoglobulin on cytotoxic lymphocytes.

Abstract: Target cell killing by lymphocytes can be induced by appropriate antibody complexed to target cell antigens. In this paper it is shown that this form of lymphocyte mediated cytotoxicity is susceptible to inhibition by third party immune complexes which compete with target cell bound antibody for receptors for immunoglobulin on the cytotoxic lymphocytes. The physical state of the complexes is investigated in relation to their inhibitory efficiency. Evidence is presented to show that soluble complexes which exist in antigen–antibody equilibrium or slight antigen excess are the most effective inhibitors. No evidence could be obtained to support the hypothesis that soluble immune complexes can induce indiscriminate cytotoxic activity in lymphocytes. The biological significance of this effect is discussed in relation to chronic inflammatory diseases.

Lymphocyte interactions in antibody responses.

Abstract: Publisher Summary The immune response of an organism to a foreign stimulus consists of a series of events initiated by the interaction of an “immunocompetent” cell and antigen There are two broad classes of immune responses: (1) “humoral immunity,” in which antibodies, characterized as immunoglobulin molecules, are synthesized, generally by plasma cells and released into the serum,( 2 ) “cellular immunity,” which can occur independently of humoral immunity and is mediated by specifically sensitized lymphocytes and is responsible for delayed-type hypersensitivity reactions, transplantation immunity, and cellular resistance to certain microorganisms, notably viruses and mycobacteria The immune system is essentially composed of two separate populations of lymphocytes: (1) thymus-dependent T lymphocytes able to recirculate from blood through certain discrete areas of the lymphoid tissues and back to blood via lymphatics and responsible for cellular immunity; (2) thymus-independent B lymphocytes (bursa-dependent in avian species) that populate the follicular complex of the lymphoid tissues and are involved in the production of plasma cells, immunoglobulins, and antibodies T and B cells synergize in the antibody response of various species of rodents to thymus-dependent antigens, both in vivo and in vitro The T cells do not produce antibody but are essential to facilitate antibody production by B cells in response to the antigen The question of the existence of specific antigen receptors on T cells is also discussed Specific immunological memory and tolerance are evident in cellular responses that are T cell-mediated and in humoral responses to thymus-independent antigens that are B cell-mediated This implies that both T and B cells display immunological specificity In systems requiring collaboration between T and B cells, the situation is more complex and it is essential to determine whether T cells, B cells, or both can dictate the specificity of the response

In Vitro Demonstration of Cell-mediated Immunity to Human Brain Tumors

Abstract: Our studies showed that patients with primary intracranial neoplasms, both well differentiated and anaplastic, intra- and extracerebral, possessed peripheral blood lymphocytes that in vitro were specifically cytotoxic to tissue-cultured, autogenous tumor cells. Some studies suggested antigenic cross-reactivity between glioblastoma cells from different patients and, moreover, between glioblastoma and melanoma cells. One melanoma patient possessed lymphocytes cytotoxic to his tumor cells and to allogeneic glioblastoma cells, as well as to the tumor cells and normal glial cells, but not to the normal fibroblasts, of a patient with a ganglioglioma.

Cytotoxic lymphocytes in melanoma patients

Abstract: Peripheral blood lymphocytes from 61 melanoma patients were tested by a microcytotoxicity test for cell-mediated immunity against melanoma cells. Lymphocytes from 13/25 patients were cytotoxic for autologous tumour cells, while lymphocytes from 31/56 patients were cytotoxic in the allogeneic situation. In the cases tested no cytotoxic reaction was found against autologous or allogeneic normal skin fibroblasts. Normal control lymphocytes were cytotoxic in 2/50 individuals tested. Lymphocytes from patients with other neoplastic diseases showed a positive cytotoxic effect in 1/18 patients tested. In seven cases lymphocytes from melanoma patients, which were cytotoxic for melanoma cells, did not show any cytotoxic effect on plated choriocarcinoma cells. There was no correlation between the presence of specifically immune lymphocytes and the clinical staging of the disease. In the serum of patients with distant metastases, preliminary results indicated the presence of factors which could block the cytotoxic effect of specifically immune lymphocytes. The data suggest that most malignant melanomas contain a common antigen which is immunogenic in patients with this neoplasm. However, individual- or subgroupspecific melanoma antigens may exist. Evidence is found that lymphocytes can lose their capacity to kill melanoma cells in the course of the disease. Change of antigenic expression or sensitivity to the killing effect of lymphocytes during culturing of the melanoma cells may explain the irregularity of some results.

Macrophage-mediated cytotoxicity against allogeneic target cells in vitro.

Abstract: A system is described in which monolayers of sensitized peritoneal macrophages destroy allogeneic target cells in vitro. The cytotoxic effect is measured by 51Cr release from labeled mastocytoma target cells. Different methods were applied to rule out any lymphocyte contamination. Stainings at different stages of the reaction excluded phagocytosis of target cells. At a ratio of 20 macrophages to 1 target cell destruction is complete after 24 h. Macrophages reacted to multiple challenges by repeated lysis of the target cells. Macrophages treated with trypsin lost their cytotoxicity but regained cytotoxic capacity 48 h after treatment. By labeling the sensitized macrophages with 51Cr it was shown that they keep full viability during the cytotoxic action.

Receptor for Antibody—Antigen Complexes used to Separate T Cells from B Cells

Abstract: LYMPHOCYTES with the capacity to bind antibody-antigen complexes to their surface1–3 are probably bone marrow-derived, B, cells, not thymus-derived, T, cells3. We now have definite evidence that such lymphocytes are indeed B cells, and will describe how this property can be utilized in a practical way for separating T cells from B cells.

B lymphocytes can be stimulated by concanavalin A in the presence of humoral factors released by T cells

Abstract: Concanavalin A (Con A) induces proliferation in thymus-derived (T) lymphocytes, whereas it does not induce DNA synthesis in bone marrow-derived (B) lymphocytes. However, in the presence of humoral factors released by normal thymus lymphocytes during 24 h in culture, B cells become competent to respond to Con A. The optimal dose of Con A for induction of proliferation in B cells treated with T cell supernatant was identical to that for T cell proliferation. Nonspecifically activated T cells were more effective than normal T cells to produce humoral factors making B cells competent to respond to Con A.

Cell-mediated immunity in periodontal disease; cytotoxicity, migration inhibition and lymphocyte transformation studies

Abstract: Cultures of peripheral blood lymphocytes from patients with gingivitis or mild periodontitis were stimulated with ultrasonicates of Veillonella alcalescens to yield an increase of 14C-thymidine incorporation and of cytotoxicity against 51Cr-labelled chicken red cells. The cell-free supernatant from the antigen-stimulated cultures inhibited migration of guinea-pig peritoneal macrophages. In patients with severe periodontitis lymphocytes showed only weak transformation but strong cytotoxic and migration-inhibitory activity. These data suggest that cell-mediated immunity against an oral Gram-negative micro-organism plays some part in the pathogenesis of periodontal disease. The advanced stage of disease, however, revealed a dissociation between lymphocyte transformation and cytotoxicity or macrophage inhibition.

Antigenic properties of murine sarcoma virus-transformed balb/3t3 nonproducer cells

Abstract: The isolation of clonal lines of murine sarcoma virus-transformed, non-producer BALB/3T3 cells has provided a model system for determining whether RNA tumor virus-transformed cells possess virus-specific transplantation antigens. MSV nonproducer cells (K-234) were clonally derived from an inbred mouse cell line, BALB/3T3. A parallel virus-producing cell line was obtained by infection of the MSV nonproducer cells with Rauscher leukemia virus. K-234 was much more tumorigenic than K-234(R). Preimmunization of syngeneic mice with either K-234(R) or with UV-inactivated Rauscher leukemia virus induced transplantation resistance to subsequent challenge with K-234(R), but not with K-234. In contrast, mice preimmunized with nonproducer cells were not made resistant to subsequent challenge with the homologous cells. Antisera prepared from mice immunized with K-234(R) were specifically cytotoxic and positive by fluorescent antibody staining for K-234(R) target cells, but not to either BALB/3T3 or K-234. The results show that MSV nonproducer cells lack detectable transplantation antigens and suggest that the transplantation resistance to the producing cells is attributable to maturing virus at the cell surface.