Cell-mediated lympholysis of trinitrophenyl-modified autologous lymphocytes. Confirmation of genetic control of response to trinitrophenyl-modified H-2 antigens by the use of anti-H-2 and anti-Ia antibodies

Splenic lymphocytes from B10.A and B10.D2 mice were sensitized in vitro to trinitrophenyl (TNP)-modified autologous spleen cells. The effector cells generated were assayed in a 51Cr-release assay on TNP-modified syngeneic or congenic spleen target cells. Effector cells from B10.A donors lysed TNP-modified H-2Kk- but not H-2Dd-region products, whereas B10.D2 effectors reacted with modified products of both the H-2Kd and H-2Dd regions. As an independent confirmation that this selective K-end lysis by B10.A effector cells is due to an H-2-linked responder cell defect (4), anti-H-2Kk but not anti-H-2Dd sera were shown to inhibit the lysis of B10.A-TNP targets by B10.A effectors. In contrast, anti-H-2Dd sera inhibited the lysis of B10.A-TNP targets by B10.D2 effectors. Anti-Ia antibodies had no detectable effect on lysis. Anti-TNP-keyhole limpet hemocyanin sera blocked the lysis of TNP-modified targets, irrespective of whether the effector cells were directed against TNP-modified autologous H-2 products or H-2 alloantigens. These results independently verify that B10. A responding lymphocytes do not generate effector cells to TNP-modified H-2Dd products, whereas B10.D2 lymphocytes do (4), and suggest that some TNP groups are sterically close to (or part of) the serologically defined H-2K- and H-2D-region antigens.     

Cell-mediated lympholysis of trinitrophenyl-modified autologous lymphocytes. Effector cell specificity to modified cell surface components controlled by H-2K and H-2D serological regions of the murine major histocompatibility complex

Splenic lymphocytes from four C57BL/10 congenic resistant mouse strains were sensitized in vitro with trinitrophenyl (TNP)-modified autologous spleen cellsmthe effector cells generated were incubated with 51-Cr-labeled unmodified or TNP-modified spleen or tumor target cells, and the percentage of specific lympholysis determined. The results obtained using syngeneic-, congenic-, recombinante, and allogeneic-modified target cells indicated that TNP modification of the target cells was a necessary but insufficient requirement for lympholysis. Intra-H-2 homology either between modified stimulating cells and modified target cells or between responding lymphocytes and modified target cells was also important in the specificity for lysis. Homology at the K serological region or at K plus I-A in the B10.A and B10BR strains, and at either the D serological region or at some other region (possibly K) in the B10.D2 and C57BL/10 strains were shown to be necessary in order to detect lympholysis. Experiments using (B10itimes C57BL/10)F1 responding lymphocytes sensitized and assayed with TNP-modified parental cells indicated that the homology required for lympholysis was between modified stimulating and modified target cellsmthe possibility is raised that histocompatibility antigens may serve in the autologous system as cell surface components which are modified by viruses or autoimmune complexes to form cell-bound modified-self antigens, which are particularly suited for cell-mediated immune reactions. Evidence is presented suggesting that H-2-linked Ir genes are expressed in the TNP-modified autologous cytotoxic system. These findings imply that the major histocompatibility complex can be functionally involved both in the response potential to and in the formation of new antigenic determinants involving modified-self components.     

Mixed lymphocyte reactivity and cell-mediated lympholysis to trinitrophenyl-modified autologous lymphocytes in C57BL/10 congenic and B10.A recombinant mouse strains

Cell-mediated lympholysis (CML) to trinitrophenyl (TNP)-modified autologous splenic lymphocytes has been recently reported in the mouse (1). Both the sensitization and effector phases of this phenomenon were shown to be T-cell mediated. Effector cell specificity studies indicated that modification of the target cells is a necessary but insufficient requirement for cytolysis, and suggested that altered cell surface components controlled by genes mapping in the mouse major histocompatibility H-2 complex (MHC) are important in the specificity of the cytotoxic reaction (1). In allogeneic models the generation of cytotoxic effector cells has been shown to be preceded or accompanied by immunogen- induced proliferation of responding lymphocytes, i.e. a mixed lymphocyte reaction (MLR) (2-5), although the generation of effectors may not necessarily always be the consequence of extensive cell proliferation (5). If the induction of cytotoxic effector lymphocytes by modified syngeneic spleen cells is characteristic of sensitization with cellular alloantigens, one would expect to find that sensitization with TNP-modified autologous cells would also induce thymidine incorporation by the responding cells in the culture. The present report demonstrates that both stimulation of thymidine incorporation and generation of cytotoxic effector cells are part of the in vitro response to TNP-modified autologous lymphocytes. However, the MLR to TNP- modified autologous cells consistently appeared to be less pronounced when compared with an allogeneic MLR, whereas the cytotoxic activity of the effector cells generated by sensitization against TNP-modified autologous cells was frequently as high as that detected against H-2 alloantigens. These two components of reactivity to “modified self” are verified in several C57BL/10 congenic and B10.A recombinant mouse strains.     

H-2-linked genetic control of murine T-cell-mediated lympholysis to autologous cells modified with low concentrations of trinitrobenzene sulfonate

Spleen cells from B10.BR and C57BL/10 (B10) mice were compared for their ability to generate primary in vitro cytotoxic responses to syngeneic cells modified with different concentrations (from 10 to 0.031 mM) of trinitrobenzene sulfonate (TNBS) (TNP-self). Although both strains generated effector cells to TNP-self in the range of 10-0.25 mM TNBS modification, effector activity of B10 cells was weaker than that of B10.BR cells. B10 spleen cells did not respond to syngeneic stimulating cells modified at 0.1 mM or lower, whereas B10.BR cells generated effector activity even when stimulated by TNP-self modified with as low as 0.031 mM TNBS. Fluorescence analysis of the modified cells using the FACS II indicated that equivalent quantities of TNP were conjugated to the surfaces of B10.BR and B10 spleen cells for any given concentration of TNBS modification. Similar strain-dependent differences were observed when the TNP was diluted out in the cultures by reducing the number of stimulating cells modified with 10 mM TNBS. These response patterns were verified by stimulating cultures of B10.BR and B10 spleen cells either with TNP conjugated to bovine serum albumin or bovine gamma globulin (B10.BR but not B10 cells responded to TNP-conjugated proteins) or with TNBS-modified glass-adherent spleen cells. The strain-dependent differences could also be detected at the effector phase, because optimally stimulated B10.BR, but not B10 effector cells, could lyse 0.1 mM TNBS-modified syngeneic target cells. The genetic parameters associated with the response and nonresponse patterns of B10.BR and B10 mice were further investigated by comparing the cytotoxic responses to low doses of TNP-self of spleen cells from the following strains: (a) C3H/HeJ (H-2k) and C3H.SW (H-2b); (b) BALB.K (H-2k) and BALb.b (h-2b); and (c) B10.A (H-2a) and B10.D2 (H-2d). The H-2k and H-2a, but not the H-2b and H-2d, strains generated cytotoxic responses to TNP-self when the syngeneic stimulators were modified with 0.1 mM TNBS. Further studies using (B10 X B10.BR)F1 responding cells and parental or F1-modified stimulating cells, indicated that the F1 cells generated cytotoxic activity to low doses of TNP in association with H-2k but not in association with H-2b self products. The results of this study indicate that H-2-linked genetic factors, expressed in the target as well as in the responding and/or stimulating cell populations, control the ability of inbred mouse strains to generate cytotoxic effector cells to low doses of TNP-self. Such dose-dependent genetic effects may be important in the regulation of immune responses activated in vivo by chronic exposure to infectious agents.     

Multiple H-2-linked immune response gene control of H-2D- associated T-cell-mediated lympholysis to trinitrophenyl-modified autologous cells: Ir-like genes mapping to the left of I-A and within the I region

One of the more recent associations of the murine H-2 major histocompatibility complex (MHC) with immune function has been the finding that cytotoxic T-effector cells generated by sensitization with viral-infected (1-6), chemically modified (7-9), or weak transplantation antigen-associated (10,11) syngeneic cells can efficiently lyse target cells which express the same viral, chemical, or weak antigenic agent, and which share the H-2K and/or H-2D regions of the MHC with the responding and/or stimulating cells. Furthermore, an additional contribution of a gene(s) within the H-2 complex has been demonstrated which controls immune response potential (Ir genes) in the generation of cytotoxic effector cells to trinitrophenyl (TNP)-modified self components (12,13). In such studies it was found that certain B10 congenic strains generated good cytotoxic responses to both TNP- modified H-2K and H-2D region products, whereas other B10 congenic strains exhibited preferential or exclusive reactivity against TNP-modified H-2K region products. Some of these recombinant strains differing in response potential to TNP- modified H-2D products expressed the same haplotype at the D end, but differed at the K end of H-2. The low responsiveness observed in the B10.A strain to TNP-modified H-2D(d) when compared to B10.D2 and (B10.A x B10.D2)F(1) for the same specificity, suggested a role of dominant Ir genes which map in K, I-A, I-B, I-J, and/or I-E (12, 14). In the present report an attemnpt was made to further map within the MHC the Ir gene(s) controlling cell-mediated lympholysis (CML) to TNP-modified H-2D(d), by using recombinant mouse strains on the A and B10 backgrounds. Irrespective of the genetic background, the s and k haplotypes at the K end generated high and low cytotoxic responses, respectively, to H-2D(d)-TNP. The intermediate responder and low responder status of the A.TL and A.AL strains, respectively, indicated that a gene mapping in the K region of H-2 influences response potential. Furthermore, the differences in the levels of cytotoxicity detected in the A.TH and A.TL strains suggested an additional I region influence. Taken together these findings raise the possibility that multiple genes mapping within different regions of the MHC control the level of T-cell-mediated cytotoxicity to chemically modified autologous cells.     

Regulation of T-cell-mediated lympholysis by the murine major histocompatibility complex. I. Preferential in vitro responses to trinitrophenyl-modified self K- and D-coded gene products in parental and F1 hybrid mouse strains

Spleen cells from H-2b,k,d C57Bl/10 congenic mice were sensitized in vitro to trinitrobenzenesulfonate (TNBS)-modified autologous spleen cells. Cold target competition studies at the lytic phase demonstrated three distinct patterns of cytotoxic responsiveness: (a) H-2b spleen cells generated approximately equivalent CTL responses against Kb and Db modified self products, (b) H-2d spleen cells generated preferential responses against Dd modified self products, and (c) H-2k spleen cells generated cytotoxic responses which could only be detected against Kk self products in association with TNP. F1 spleen cells were sensitized against autologous TNBS-treated cells. The results showed that, although H-2b parental cells generated approximately equivalent Kb-TNP- and Db-TNP-specific CTL, the presence of the H-2b haplotype did not result in the generation of (a) Dk-TNP CTL response by (H-2b x H-2k) spleen cells, nor (b) a Db CTL response by (H-2b x H-2a) F1 spleen cells. Additionally, (H-2d x H-2k) F1 cells failed to generate detectable Dd-TNP-specific CTL, although H-2d parental cells generated D-regional-specific CTL. The findings demonstrated that these F1 response patterns paralleled those of the H-2k and H-2a parents, i.e. weak or no D-region TNP-specific CTL were induced. Because (H-2d x H-2a) F1 responders stimulated with H-2d TNBS-treated cells did generate good Dd TNP responses, the results illustrated that the presence of responder genes was not sufficient to result in a D-region TNP CML. It is suggested that the absence of Kk alleles on the stimulating population is necessary for the generation of D-region TNP CTL in these F1's. Mechanisms which could account for these response patterns in parental F1 mice are discussed including immunodominance, suppression, T-cell response , and Ir-gene defects.     

Targeting autoantigen to B cells prevents the induction of a cell- mediated autoimmune disease in rats

Immunization protocols that induce high levels of delayed-type hypersensitivity are often associated with low levels of antibody production, whereas alternative immunization strategies can produce the opposite effect. This reciprocal relationship appears to depend, at least in part, on the fact that T cell-derived lymphokines that are predominantly involved in one type of response inhibit the development of those T cells that promote the alternative one. Such a regulatory mechanism is likely to be bistable in that whenever one form of response is established, spontaneous development of the alternative one will be inhibited. We have applied this concept to the control of a cell-mediated autoimmune disease in rats. By covalently linking the autoantigen to anti-IgD antibody, we have targeted it to B cells for presentation to antigen-specific T cells. This form of presentation favors antibody production and may be expected to antagonize the cell-mediated disease-inducing response to the same antigen. To test this hypothesis, use was made of the fact that experimental allergic encephalomyelitis (EAE), when induced with the encephalitogenic peptide of guinea pig myelin basic protein, is purely a cell-mediated disease. The experiments show that Lewis rats, immunized with the peptide in its encephalitogenic form, were protected from disease when simultaneously injected with the peptide coupled to anti-IgD monoclonal antibodies. Control experiments showed that neither peptide nor anti-IgD alone were protective, and the peptide covalently coupled to irrelevant antibodies also failed to protect. Spleen cells from animals protected from disease by the anti-IgD-peptide conjugate, when activated in vitro with the encephalitogen, were able to transfer EAE to naive recipients. The results demonstrate that a cell-mediated immune response can be controlled by appropriate targeting of the specific antigen without inducing T cell anergy and suggest a potential strategy for preventing autoimmune diseases that are essentially cell-mediated in type.     

Mechanisms of genetic resistance to Friend virus leukemia. III. Susceptibility of mitogen-responsive lymphocytes mediated by T cells

Friend leukemia virus (FV) suppressed the proliferative responses of spleen, lymph node, marrow, and thymus cell populations to various T- and B-cell mitogens. Cells taken from mice, e.g. BALB/c genetically susceptible to leukemogenesis in vivo were much more susceptible to suppression of mitogenesis in vitro than similar cells from genetically resistant mice, e.g., C57BL/6. Nylon wool-purified splenic T cells from BALB/c and C3H mice lost susceptibility to FV-induced suppression of mitogenesis but became suppressible by addition of 10% unfiltered spleen cell. Thus, FV mediates in vitro suppression of lymphocyte proliferation indirectly by "activating" a suppressor cell. The suppressor cell adhered to nylon wool but not to glass wool or rayon wool columns. Pretreatment of spleen cells with carbonyl iron and a magnet did not abrogate the suppressor cell function. Suppressor cells were not eliminated by treatment with rabbit antimouse immunoglobulin (7S) and complement (C). However, high concentrations of anti-Thy-1 plus C destroyed suppressor cells of the spleen; thymic suppressor cells were much more susceptible to anti-Thy-1 serum. Nude athymic mice were devoid of suppressor cells and their B-cell proliferation was relatively resistant to FV-induced suppression in vitro. The suppressor cells in the thymus (but not in the spleen) were eliminated by treatment of mice with cortisol. Thus, FV appears to mediate its suppressive effect on mitogen-responsive lymphocytes by affecting "T-suppressor cells." Spleen cells from C57BL/6 mice treated with 89Sr to destroy marrow-dependent (M) cells were much more suppressible by FV in virto than normal C57BL/6 spleen cells. However, nylon-filtered spleen cells of 89Sr-treated C57BL/6 mice were resistant to FV-induced suppression in vitro, indicating that the susceptibility of spleen cells from 89Sr-treated B6 mice is also mediated by suppressor cells. Normal B6 splenic T cells were rendered susceptible to FV-induced suppression of mitogenesis by addition of 10% spleen cells from 89Sr-treated B6 mice. Thus, M cells appear to regulate the numbers and/or functions of T-suppressor cells which in turn mediate the immunosuppressive effects of FV in vitro. Neither mitogen-responsive lymphocytes nor T-suppressor cells are genetically resistant or susceptible to FV. The genetic resistance to FV is apparently a function of M cells, both in vitro as well as in vivo.     

Cell-mediated lympholysis of N-(3-nitro-4-hydroxy-5-iodophenylacetyl)- beta-anaylglycylglycyl-modified autologous lymphocytes. Effector cell specificity to modified cell surface components controlled by the H-2K and H-2D serological regions of the murine major histocompatibility complex

Splenic lymphocytes from four C57BL/10 congenic mouse strains were sensitized in vitro to N(-3-nitro-4-hydroxy-5-iodophenylacetyl)-beta-alanylglycylglycyl-(N) modified autologous lymphocytes. The effector cells generated after 5 days of culture were assayed on a series of either N-modified phytohemagglutinin-stimulated spleen cells or N-modified tumor cells. The results indicated in all cases that both N modification of the targets and H-2 homology between the modified stimulating and target cells are required for lysis to occur. In each case the effector cells were found to lyse N-modified target cells only when there was homology at either or both ends of the major histocompatibility complex (MHC) between the stimulator and target cells. B10.BR lysed targets sharing alleles at K (or K plus I-A) and/or at D. B10.A effector cell specificity was mapped to K (or K plus I-A) and/or the D half of the MHC (D or D plus I-C and/or S). The two regions of specificity determined for B10.D2 effector cells were D (or D plus S plus I-C) and a region not including D of the MHC. C57BL/10 effector cells lysed N-modified targets only if there was target cell H-2 homology at K, I-A, and I-B or at the D serological region. As in the trinitrophenyl (TNP) system (6) B10.BR and B10.A effector cells lysed targets sharing K end H-2 serological regions greater than target cells sharing D-end serological regions. The C57BL/10 effector cells were shown to react to the K end greater than the D end, which differed from the equal reactivity seen in the TNP system for this strain. The data are consistent with the hypothesis that the antigen recognized by the effector cell includes an altered H-2 serological cell surface product. That the reaction is not "hapten specific" and the H-2 homology is required only for effector:target cell interaction was excluded by the use of two F1 combinations in which lysis of only N-modified target cells sharing the H-2 haplotype with the stimulating parental strain was obtained. Finally, it was demonstrated that N and TNP modification create distinct new antigenic determinants, since an effector cell sensitized to one modifying agent will lyse only H-2 matched target modified with that same modifying agent.     

Recognitive specificity of human cytotoxic T lymphocytes. I. Antigen- specific inhibition of human cell-mediated lympholysis

The specificity of antigen recognition by in vitro sensitized human cytotoxic T lymphocytes (CTLs) has been studied using a sensitive cell-mediated lympholysis (CML) assay. Frequently, high levels of cytotoxicity are observed on third-party targets unrelated to sensitizing or responding cells; however, no cytotoxicity differing significantly from zero has been observed on targets autologous to the responding CTLs. This "cross-killing" of third-party target cells has been observed when stimulating and third-party cells bear no cross-reacting serologically defined (SD) antigens, thought to be the target antigens recognized by CTLs. CML-blocking studies, using unlabeled normal human lymphocytes to inhibit 51Cr release from radiolabeled target cells, have shown that cross-killing, even in the absence of shared SD determinants, results from CTLs recognizing antigens shared by the third-party targets and the initial stimulating population. Furthermore, these antigens have been mapped to the major histocompatibility complex (MHC). The ability of human CTLs to specifically recognize MHC-controlled antigens not detected serologically suggests that SD antigens may be recognized differently by alloantisera and CTLs, or that MHC antigens other than SD may be the targets of CTLs in CML.     

Volume regulation by human lymphocytes. Identification of differences between the two major lymphocyte subpopulations.

Following exposure to hypotonic media, human peripheral blood lymphocytes swell initially but restore their isotonic volume within minutes. In contrast, tonsillar lymphocytes demonstrate a similar initial phase of swelling but fail to restore their isotonic volume. We have studied the ionic basis for this second or regulatory volume decrease (RVD) phase using lymphocytes from peripheral blood, tonsil, and thymus. RVD was characterized by 86Rb efflux and a decrease in K+ content. The increase in K+ permeability in response to hypotonic challenge was characteristic for T lymphocytes obtained from peripheral blood, tonsil, or thymus. B lymphocytes showed only a modest increase in K+ permeability and consequently little RVD. The data confirm that the response of peripheral blood and tonsillar lymphocytes to a hypotonic environment can be accounted for by differences in the proportions of T and B cells, and the differential behaviour of B and T lymphocytes is based on differences in membrane permeability to K+ upon swelling.     

Mechanisms of genetic resistance to Friend virus leukemia in mice. II. Resistance of mitogen-responsive lymphocytes mediated by marrow- dependent cells

Friend leukemia virus suppresses the proliferative responses of normal thymus-dependent (T) and bursa equivalent-dependent (B) lymphocytes from spleen, thymus, lymph node, and bone marrow to mitogens. The suppressive effect of Friend virus complex (FV) requires fully infectious virions. Friend erythroleukemic cells, washed to removed extracellular virus, fail to suppress concanavalin A (Con-A)-induced mitogenesis of normal spleen cells. This indicates that FV does not mediate its immunosuppressive effect via transformed erythropoietic cells. The in vitro suppressive effect of FV on lymphocyte mitogenesis is under host genetic control. Spleen, bone marrow, and thymus cells from strains of mice susceptible to FV-induced leukemogenesis in vivo were quite susceptible to the suppressive effects of FV in vitro. On the other hand, similar cells from strains of mice such as C57BL/6 resistant to Friend erythroleukemia, were quite resistant to in virto immunosuppression by FV. Mitogenesis of splenic T cells from resistant B6 mice, previously treated with 89Sr, became susceptible to suppression by FV. This indicated that the in vitro resistance of lymphocytes to FV-induced suppression is not an intrinsic property of T cells, but is controlled by marrow-dependent (M) cells which are selectively eliminated by treatment with 89Sr. M-cell function does not develop in mice less than 3-wk old. The Con A response by thymus cells from 2-wk-old B6 mice was susceptible to suppression by FV, further supporting the concept that M cells may regulate the genetic resistance to FV.     

Identification of a subpopulation of lymphocytes in human peripheral blood cytotoxic to autologous fibroblasts

A naturally occurring subpopulation of human peripheral blood lymphocytes is cytotoxic to autologous and/or allogeneic fibroblasts. The autocytotoxic lymphocytes have a receptor for the third component of complement and for aggregated gamma globulin, do not form rosettes with sheep red blood cells, and are not removed by passage through nylon. The autocytotoxic subpopulation is not present in the thymus and tonsils of normal children or in the peripheral blood of individuals with X-linked agammaglobulinemia. Fibroblast absorption experiments demonstrate that the autocytotoxic cells are "sensitized" to antigens expressed on allogeneic fibroblasts in addition to the antigens expressed on autologous cells. Some normal individuals have a second subpopulation of lymphocytes that may "regulate" the autocytotoxic cells. The relevance of these observations to the murine autocytotoxic cells is discussed.     

Importance of immunoglobulin isotype in human antibody-dependent, cell- mediated cytotoxicity directed by murine monoclonal antibodies

Using the fluorescence activated cell sorter to select rare IgG2a- and IgG2b-producing variants, we developed switch variant families of hybridomas from IgG1-producing hybridomas, ME1 and MA2.1. The IgG2a and IgG2b antibodies produced by such switch variants have the same binding activities for HLA as the IgG1 antibodies produced by the parent hybridomas. Using these antibodies, we directly compared the IgG1, IgG2a, and IgG2b murine Ig isotypes for their capacities to direct human peripheral blood lymphocytes (PBL) in antibody-dependent cell-mediated cytotoxicity (ADCC) against a B lymphoblastoid cell line. We demonstrate that, for antibodies of identical binding affinity and specificity, the murine IgG2a isotype is the most effective in directing ADCC by human effector cells. The murine IgG2b directs intermediate levels of ADCC activity while IgG1 is inactive. We identified the effector cells in human PBL that mediate IgG2a or IgG2b ADCC as nonadherent killer (K) cells. These cells express the C3bi receptor and have cytolytic activity which is specifically blocked by a monoclonal antibody (anti-Leu-11a) that binds the Fc receptor (FcR) of such cells. Finally, FcR-bearing K cells bind to target cell-bound, rather than free, IgG2a or IgG2b molecules.     

Actin mediated regulation of muscle contraction.

Striated and smooth muscles have different mechanisms of regulation of contraction which can be the basis for selective pharmacological alteration of the contractility of these muscle types. The progression in our understanding of the tropomyosin-troponin regulatory system of striated muscle from the early 1970s through the early 1990s is described along with key concepts required for understanding this complex system. This review also examines the recent history of the putative contractile regulatory proteins of smooth muscle, caldesmon and calponin. A contrast is made between the actin linked regulatory systems of striated and smooth muscle.     

TNF-alpha secretion and apoptosis of lymphocytes mediated by gene transfer

Efficient gene transfer of lymphocytes is extremely difficult. Apoptosis may play a role in this gene transfer resistance of lymphocytes. Here we show that transfection of lymphocytes via non-viral vectors leads to induction of apoptosis in a significant proportion of cells. Since apoptosis may be mediated via tumor necrosis factor d (TNF-alpha) and the TNF-alpha receptor pathway, we studied the amount of TNF-alpha secreted by lymphocytes transfected without gene insert. TNF-alpha secretion was dependent on the gene transfer method used. High amounts were detected using receptor-mediated gene transfer and lipofection. In contrast, only low amounts of TNF-alpha were detected after electroporation and retroviral gene transfer. In receptor-mediated gene transfer, TNF-alpha secretion was due to the use of anti-CD3 antibody. Transfection of lymphocytes led to selective decrease in CD120b/TNF-alpha receptor II (TNFR-2)-positive cells. Induction of apoptosis and necrosis mediated by TNF-alpha via TNFR-2 (p80) was partially blocked using a neutralizing anti-TNF-alpha antibody. Blockage of apoptosis and necrosis could be further increased by adding anti-Fas-ligand (FasL) antibody, suggesting that induction of apoptosis via FasL and Fas receptor (Apo-1/CD95) may also play a role. This blockage led to a significant increase in the proliferation rate of lymphocytes transfected with cytokine genes. In conclusion, various gene transfer techniques led to TNF-alpha secretion, apoptosis and necrosis of lymphocytes. Apoptosis and necrosis could be partially blocked using a neutralizing anti-TNF-alpha antibody.     

Spinal fluid lymphocytes responsive to autologous and allogeneic cells in multiple sclerosis and control individuals.

Spinal fluid lymphocytes from multiple sclerosis (MS) patients and controls were stimulated with either autologous non-T cells or with allogeneic non-T cells followed by stimulation with autologous non-T lymphocytes. Cells responding to these stimuli were cloned and their proliferative responses to autologous and allogeneic MS and normal non-T cells were measured. Large numbers of clones with specific patterns of reaction to both autologous and allogeneic cells were obtained from lymphocytes in MS cerebrospinal fluid (CSF), but only occasionally from cells in control CSF. Patterns of responses among clones from a particular CSF were similar and often identical, which suggested that cells in MS CSF were relatively restricted in their specificities. Surface antigen phenotyping of the clones showed them to be predominantly OKT4+, with 13% OKT8+ and 11% OKT4+8+. Peripheral T cells that were stimulated and cultured in parallel with CSF cells were different in that they usually did not give rise to as many clones nor were their patterns of response similar. Many CSF clones were heteroclitic, that is they responded to particular allogeneic cells but not autologous cells. Lymphocytes in MS CSF thus appear to represent a selected population of cells with a high frequency of responsiveness to autologous and allogeneic antigens. Such responses may be evidence for immune regulation within the central nervous system or could represent responses to altered-self antigens.