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We have previously shown that the generation of an NK1.1 + TCRαβ + (NK-T) cell population is severely impaired in an alymphoplasia mutant ( aly/aly ) mouse strain and the defect resides in the thymic environment. In the present study, to elucidate the thymic stromal component(s) that affects the development of NK-T cells, radiation bone marrow chimeras were established with the aly/aly mouse as a donor and either the β2 microglobulin knockout (β2m−/−) or the CD1d1−/− mouse that also lacks the NK-T cell population as a recipient. A normal population of NK-T cells with a typical NK-T phenotype and functions was detected in both the thymus and the spleen of these chimeras. These findings indicated that a radiation-resistant CD1 − component of the thymus supported generation of functional NK-T cells from aly/aly precursors. Furthermore, transfer of an intact medullary thymic epithelial cell line into aly/aly thymus significantly induced the generation of NK-T cells in the thymus. These findings suggest that CD1 molecules of bone marrow-derived cells and the medullary epithelial cells acted in concert in the generation of the NK-T cell population and that a function(s) of the medullary thymic epithelial cells other than direct presentation of CD1 molecules to the NK-T precursors is indispensable for the development of NK-T cells.

It has been shown that macrophage migration inhibitory factor (MIF) modulates not only macrophage functions, but also T cell functions. However, detailed analysis of the MIF function on responses of various T cell subpopulations remained to be elucidated. In this report, using a neutralizing anti-MIF monoclonal antibody (mAb) we examined MIF functions on various T cell lineages. It was shown that anti-MIF mAb inhibited antigen-specific responses of both IFN-γ producing and IL-4 producing T cells. The inhibition appeared to be related to blockade of the signal pathway via T cell receptor (TCR) but not that via IL-2 receptor (IL-2R). However, the anti-MIF mAb showed no inhibitory effect on NK-T cell responses stimulated through TCR. These results suggest that MIF is involved in the signal pathway via TCR in mainstream T cells but not in NK-T cells.

Ageing is usually accompanied by a decline in immune and neuroendocrine functions. To elucidate the mechanisms underlying age-related immunosuppression, the functions and surface phenotypes of peritoneal cells in the monocyte/macrophage lineage from old mice were investigated. The role of glucocorticoids (GC) in the immunomodulation was also examined. Proliferative responses of spleen cells from control mice stimulated with concanavalin A (Con A) were significantly suppressed by adding peritoneal exudate cells from old mice. Flow cytometry analysis revealed that the proportion of MAC-1+ cells with a high density of type II or type III receptor for the Fc portion of IgG (Fc gamma RII/IIIbright cells) was increased markedly in the periotoneal exudate cells from old mice. The prominent suppressor activity for Con A responses of control spleen cells was found in the Fc gamma RII/IIIbright cells, whereas MAC-1+ cells with a low density of Fc gamma RII/III (Fc gamma RII/IIIdull cells) did not suppress the Con A responses. On the other hand, both the basal corticosterone concentrations in serum and the mRNA expression for GC receptor in peritoneal exudate cells increased significantly in old mice. Furthermore, the proportion of Fc gamma RII/IIIbright cells in peritoneal exudate cells from old mice was normalized on administration of the GC antagonist RU 38,486 (mifepristone). These results suggest that the increase in basal corticosterone concentrations in old mice induces the generation of Fc gamma RII/IIIbright suppressor cells, possibly leading to the immune-suppressive state.

Minor lymphocyte stimulatory (Mls) Ag are super Ag that stimulate a high proportion of T cells of a specific TCR V beta family. One of the super Ag, Mls-1a, which is recognized mainly by TCR V beta 6+ and V beta 8.1+ T cells, has recently been linked to the response to product of the open reading frame in 3'-long terminal repeat of endogenous mammary tumor virus, MTV-7. It is quite certain that B cells are able to produce and also to present the Mls-1a Ag. However, it remains to be determined whether other cell types, especially T cells, produce Mls-1a Ag. In this study using highly purified T cell subpopulations, capacity to produce Mls-1a Ag was analyzed by calculating the proportion of Mls-1a reactive V beta 6+ or V beta 8.1+ T cells in responding cell populations. We found that nonstimulated CD8+ T cells produced a low amount of Mls-1a Ag, and the capacity to do so was considerably increased by stimulation with immobilized anti-TCR mAb. By contrast, nonstimulated CD4+ T cells did not produce Mls-1a Ag at all. Even when CD4+ T cells were activated via TCR signaling with immobilized anti-TCR mAb, CD4+ T cells did not produce Mls-1a Ag. However, CD4+ T cells primed with conventional Ag in vivo produced Mls-1a Ag on restimulation with that specific Ag in vitro. These findings indicate that not only CD8+ T cells but also CD4+ T cells can produce Mls-1a Ag on appropriate stimulation, although different mechanisms for Mls-1a production may operate between the CD4+ and CD8+ T cells.

Functions of CD4-8-TCR alpha beta+ thymocytes, which are characterized by predominant usage of V beta 8.2 TCR, have remained unclear. In this study, we found that the CD4-8-TCR alpha beta + thymocytes expressed NK1.1 Ag and IL-2R beta-chain but not IL-2R alpha-chain. When the CD4-8- TCR alpha beta + thymocytes were cultured in the presence of IL-2, the CD4-8-TCR alpha beta + thymocytes vigorously proliferated. After 7 days of culture in the presence of 1000 U/ml of IL-2, approximately half of the CD4-8-TCR alpha beta + thymocytes lost NK1.1 Ag. However, the remaining half of the CD4-8-TCR alpha beta + cells showed increasing levels of NK1.1 Ag and acquired killer activity against tumor cells such as YAC-1, P815, and EL-4. These cells also killed syngeneic as well as allogeneic thymocytes. The LAK activity by the NK1.1+ CD4-8-TCR alpha beta + thymocytes was not inhibited by anti-NK1.1, anti-TCR alpha beta, or anti-CD44 mAb but was partially inhibited by anti-LFA-1 mAb. These findings indicate that the CD4-8-TCR alpha beta + thymocyte population can be divided into two population on the basis of NK1.1 expression after culture in the presence of IL-2. The NK1.1 Ag expression on the cultured CD4-8-TCR alpha beta + seems to be correlated to acquisition of LAK activity, although the NK1.1 Ag itself may not be directly involved in the target cell recognition. The present data suggest that the CD4-8- TCR alpha beta + thymocyte population is a functional T cell lineage which may serve as cells of immune defense and/or immune regulation.

Immunoregulatory states induced by i.p. inoculation with the metazoan parasite Echinococcus multilocularis in the murine system were investigated. Proliferative responses and IL-2 production induced by Con A in spleen cells from BALB/c mice were significantly depressed at an early stage after infection with E. multilocularis protoscoleces (PSC). Addition of plastic-adherent cells from normal syngeneic mice to the nonadherent spleen cells from infected mice did not restore the depressed Con A responsiveness. On the other hand, exogenous IL-2 reconstituted completely the proliferative responses to Con A. Flow cytometry analysis revealed that CD4- CD8+ cells with a low density of CD8 Ag (CD8dull cells) increased in spleens from infected mice 2 weeks after inoculation. Addition of the spleen cell subpopulation containing the CD8dull cells, but not that depleted of the CD8dull cells, to normal spleen cells resulted in marked suppression of the Con A responses. These findings suggest that the CD8dull cells detected in spleens of mice inoculated with E. multilocularis PSC may play a key role in the suppressive regulation of immune responses. The relevance of the immune suppression seen in the early stages of experimental infection with E. multilocularis PSC to the eventual establishment of a host-parasite relationship is discussed.

症例は69歳女性.特発性器質化肺炎としてステロイド治療を開始し,自他覚所見は速やかに改善した.しかし,経過中行った検索にてCoxiella burnetiiに対する血清抗体価上昇,血液PCR陽性であったため, Q熱が器質化肺炎の原因と考えられた. Q熱については,診断法が一般的でなく市中肺炎の原因としても見逃されていることが多いとされており,特発性器質化肺炎と診断されている症例の中に, Q熱によって引き起こされている症例が少なからず存在する可能性がある.

Lethally irradiated AKR mice received BMT from H-2D and minor lymphocyte stimulatory (Mls)-1 disparate B10.A mice. No GVHD signs were detected in AKR recipients of T cell-depleted BM cells (1 x 10(7)) alone ([B10.A --AKR] T-). When B10.A splenic T cells (1 x 10(5)) were injected in addition to T cell-depleted BM cells ([B10.A --AKR] T+), overt GVHD was observed. [B10.A --AKR] T+ chimeras recovered from the GVHD 8 weeks after BMT. In T cells from these [B10.A --AKR] T+ chimeras, a substantial population of Mls-1a-reactive Vbeta6+ T cells was present, whereas the Vbeta6+ cells were deleted in [B10.A --AKR] T- chimeras. T cells from [B10.A --AKR] T+ chimeras showed considerable MLR but no CTL response against AKR cells (split tolerance). Upon stimulation with AKR stimulators or anti-CD3 MoAb, T cells from [B10.A --AKR] T+ chimeras produced significantly more IL-4 but significantly less IFN-gamma compared with those from [B10.A --AKR] T- chimeras or unmanipulated B10.A mice. The serum level of IgG1 in [B10.A --AKR] T+ chimeras was also significantly higher than that in [B10.A --AKR] T- or B10.A mice. The present findings suggest that the split tolerance observed in BMT chimeras recovered from GVHD is attributable to the Th2 dominant state.

The proportion of cells with a high density of ED2 (ED2high cells) in peritoneal cells from old rats was significantly lower than that from young rats. The expression of major histocompatibility complex class II (MHC class II) molecules, the antigen presentation, production of interleukin (IL)-1beta and IL-6, and nuclear factor-kappaB activity in ED2high cells were markedly higher than those in cells with a low density of ED2 (ED2low cells), although no significant difference was observed in the expression of MHC class II molecules and the antigen presentation between ED2high cells from young and old rats. Meanwhile, basal corticosterone concentration in serum and glucocorticoid (GC) receptor mRNA expression in peritoneal cells increased significantly in old rats. The proportion of ED2high cells was increased by adrenalectomy in young rats. Furthermore, nuclear translocation of GC receptor was observed in ED2low cells, whereas GC receptor was detected in cytoplasmic extracts from ED2high cells. These results suggest that the decrease in functional ED2high macrophages with age results in the age-associated decline of immune responses, which is regulated, in part, by the basal GC concentration.

To investigate pathogenesis underlying endogenous uveitis, macrophage migration inhibitory factor (MIF) was quantified in sera of patients.Sera were obtained from the 55 patients with uveitis (24 with Behçet's disease; 9 with Vogt-Koyanagi-Harada's [VKH] disease; 22 with sarcoidosis) and 58 healthy control subjects. MIF levels were determined by a human MIF enzyme-linked immunosorbent assay.The mean MIF levels in the sera of the patients with Behçet's disease, VKH disease, and sarcoidosis and of healthy control subjects were 60.4+/-9.0 (mean+/-SE) ng/ml, 16.5+/-2.9 ng/ml, 27.1+/-5.6 ng/ml, and 5.4+/-0.04 ng/ml, respectively. The average levels of MIF in the sera of uveitis patients were significantly higher (P0.0001) than those of healthy control subjects. The high levels of MIF were especially noted in patients with Behçet's disease at the ocular exacerbation stage and patients with sarcoidosis at the severe uveitis stage.Significant increase of MIF in sera was characteristic of uveitis, and MIF may be a usefull laboratory parameter to use to comprehend the clinical course of uveitis.

Ageing is usually accompanied by a decline in immune and neuroendocrine functions. To elucidate the mechanisms underlying age-related immunosuppression, the functions and surface phenotypes of peritoneal cells in the monocyte/macrophage lineage from old mice were investigated. The role of glucocorticoids (GC) in the immunomodulation was also examined. Proliferative responses of spleen cells from control mice stimulated with concanavalin A (Con A) were significantly suppressed by adding peritoneal exudate cells from old mice. Flow cytometry analysis revealed that the proportion of MAC-1+ cells with a high density of type II or type III receptor for the Fc portion of IgG (Fc gamma RII/IIIbright cells) was increased markedly in the periotoneal exudate cells from old mice. The prominent suppressor activity for Con A responses of control spleen cells was found in the Fc gamma RII/IIIbright cells, whereas MAC-1+ cells with a low density of Fc gamma RII/III (Fc gamma RII/IIIdull cells) did not suppress the Con A responses. On the other hand, both the basal corticosterone concentrations in serum and the mRNA expression for GC receptor in peritoneal exudate cells increased significantly in old mice. Furthermore, the proportion of Fc gamma RII/IIIbright cells in peritoneal exudate cells from old mice was normalized on administration of the GC antagonist RU 38,486 (mifepristone). These results suggest that the increase in basal corticosterone concentrations in old mice induces the generation of Fc gamma RII/IIIbright suppressor cells, possibly leading to the immune-suppressive state.

Experimental autoimmune uveoretinitis (EAU) can be induced in rats by interphotoreceptor retinoid-binding protein (IRBP), and served as a model for human uveitis. Using IRBP-derived peptide R16, we investigated the MHC and non-MHC genes' effect on the regulation and susceptibility to EAU. EAU-high susceptible LEW (RT1l), EAU-low susceptible WKAH (RT1k), and WKAH.1L rats which carry RT1l and WKAH background were immunized with 2 nmol of R16. One hundred percent of LEW rats developed EAU and 92.9% of WKAH. 1L rats. Only, 18.8% of WKAH rats developed EAU. Among these strains tested, the severity of EAU was 2.06 in LEW, 1.23 in WKAH.1L, and 0.38 in WKAH. R16 evoked substantial proliferative responses in all these strains. The present data suggest that both MHC and non-MHC genes play distinct roles in development of EAU.

Addition of protoscoleces (PSC) of Echinococcus multiocularis suppressed proliferative responses in spleen cells stimulated with concanavalin A (Con A) on day 3 of culture. The suppression was not observed in the spleen cell population depleted of CD8+ cells but observed in the population depleted of CD4+ cells, suggesting the involvement of the CD8+ T cells in the apparent suppression. Indeed, flow cytometry analysis revealed that the proportion of CD8+ cells markedly increased in the Con A cultures containing PSC. Furthermore, when spleen cells were co-cultured with PSC alone, marked increase in the proportion of CD8+ cells as well as B220+ cells was observed. Addition of these increasing CD8+ cells suppressed the proliferative responses of fresh spleen cells stimulated with Con A. These findings suggest that the low responsiveness of spleen cells to Con A on day 3 of culture in the presence of PSC is attributable to an active suppressor mechanism including CD8+ T-suppressor cells generated by stimulation with PSC.

Effects of acute cold stress (5 degrees C for 24 h) on the functions of peritoneal macrophages and the mechanisms for controlling host homeostasis were investigated in mice. Phagocytic activity and expression of the cell surface adhesion molecule CD11b/CD18 were markedly increased in peritoneal exudate cells by acute cold stress. These alterations were attributable to an increased number and phenotypical changes of adherent cells from acute cold-stressed mice. On the other hand, a lipopolysaccharide-induced activity of src-family tyrosine kinase Fgr, an expression of interleukin-1beta (IL-1 beta) mRNA, and a bioactivity of IL-1 in the culture supernatants of adherent cells from acute cold-stressed mice were markedly lower than those from control mice. A time course study revealed that the number of adherent cells in peritoneal exudate cells was markedly increased in mice exposed to cold for 24 h but returned to normal numbers when mice were exposed to cold for 72 h. DNA fragmentation and Annexin-V(+) cells were observed in peritoneal exudate cells from acute-cold stressed mice. Thus, cold stress activated macrophages but these macrophages were destined to be eliminated by apoptosis.

Irradiation bone marrow chimeras were established by reconstitution of lethally irradiated AKR mice with C57BL/10 marrow cells to permit serial analysis of the developing reactivities of lymphocytes from such chimeras, [B10----AKR], against donor, host, or third party antigens. We found that substantial proliferative responses to Ia antigens of the recipient strain and also to third party antigens were generated by the thymocytes obtained from the irradiation chimeras at an early stage after bone marrow reconstitution. The majority of the responding thymocytes had surfaces lacking demonstrable peanut agglutinin receptors and were donor type Thy-1+, Ly-2-, and L3T4+ in both anti-recipient and anti-third party MLR. In anti-host responses, however, Ly-2+ thymocytes seemed to be at least partially involved. This capacity of thymus cells to mount a response to antigens of the recipient strain declined shortly thereafter, whereas the capacity to mount MLR against third party antigens persisted. The spleen cells of [B10----AKR] chimeras at the same time developed a more durable capability to exhibit anti-host reactivities and a permanent capability of reacting to third party allo-antigens. The stimulator antigens were Ia molecules on the stimulator cells in both anti-recipient and anti-third party MLR. The responding splenocytes were of donor origin and most of them had Thy-1+, Ly-1+2-, and L3T4+ phenotype.

Changes in proportions of the Fc and complement receptor (FcR, CR) positive T lymphocytesfrom guinea pigs following their interaction with rabbit erythrocytes (ER) were studied using EA and EAC rosette forming assays. Significant increases in the percentages of EA and EAC rosette forming cell (RFC) were observed when thymocytes or lymph node cells were assayed after ER rosette formation. Furthermore, T-enriched fraction by the E R monolayer adherence technique also showed similar or somewhat higher increases in the proportions of both EA and EAC RFC than those of unfractionated cells after contact with ER. The double rosette assay by ER with EA or EAC showed that 50–80 % of the Fc and/or complement receptor positive lymphocytes bound rabbit erythrocytes simultaneously. These findings strongly suggest that at least a subset of the guinea pig T cells is altered to express Fc and/or complement receptors on their surfaces following the interaction with E R .

Two monoclonal antibodies (MoAb) 1E4 and ISCR3, which detect class II antigens across species barriers, were studied for their inhibitory effects on human and murine T cell proliferative responses to purified protein derivative of tuberculin (PPD)The 1E4 detected at least a polymorphic determinant on I-A molecules from mice carrying the H-2 b haplotype, and the ISCR3 detected the Ia.7 determinant on I-E moleculesNevertheless, both 1E4 and ISCR3 recognized monomorphic determinants on HLA-DR antigens (human I-E equivalent molecules), but not on HLA-DQ antigens (human I-A equivalent molecules)It was demonstrated that 1E4 significantly inhibited PPD-specific responses of T cells from Ib-bearing miceIn contrast, ISCR3 showed marginal effects on the responses of mice bearing Ia.7However, in the human system both 1E4 and ISCR3 reduced proliferative responses to PPDThese results suggest that a functional difference exists between humans and mice in the I subregion products involved in the T cell proliferative responses to PPD.

Protection and delayed-type hypersensitivity (DTH) to the facultative intracellular bacterium Listeria monocytogenes (L.m.) were studied in allogeneic and syngeneic bone marrow chimeras. Lethally irradiated AKR (H-2k) mice were successfully reconstituted with marrow cells from C57BL/10 (B10) (H-2b), B10 H-2-recombinant strains or syngeneic mice. Irradiated AKR mice reconstituted with marrow cells from H-2-compatible B10.BR mice, [BR----AKR], as well as syngeneic marrow cells, [AKR----AKR], showed a normal level of responsiveness to the challenge stimulation with the listeria antigens when DTH was evaluated by footpad reactions. These mice also showed vigorous activities in acquired resistance to the L.m. By contrast, chimeric mice that had total or partial histoincompatibility at the H-2 determinants between donor and recipient, [B10----AKR], [B10.AQR----AKR], [B10.A(4R)----AKR], or [B10.A(5R)----AKR], were almost completely unresponsive in DTH and antibacterial immunity. However, when [B10----AKR] H-2-incompatible chimeras had been immunized with killed L.m. before challenge with live L.m., these mice manifested considerable DTH and resistance to L.m. These observations suggest that compatibility at the entire MHC between donor and recipient is required for bone marrow chimeras to be able to manifest DTH and protection against L.m. after a short-term immunization schedule. However, this requirement is overcome by a preceding or more prolonged period of immunization with L.m. antigens. These antigens, together with marrow-derived antigen-presenting cells, can then stimulate and expand cell populations that are restricted to the MHC (H-2) products of the donor type.

C57BL/6 (B6) mice are high responders whereas C3H/He (C3H) mice are low responders of lung granuloma response to a BCG cell-wall vaccine (BCG CW). Studies with allogeneic bone-marrow chimaeras and tetraparental bone-marrow chimaeras demonstrated clearly that the response is dependent on the cells derived from B6 bone marrow. Cell transfer experiments on these chimaeric mice as well as on T cell-depleted mice indicated that macrophages of C3H origin were responsible for the low responsiveness observed. Alveolar macrophages collected from tetraparental bone-marrow chimaeras which had received intravenously BCG CW 4 weeks before showed the same H-2b/H-2k ratio as that of spleen lymphocytes, thus it was proved that efferent phase of lung granuloma response was not impaired in C3H mice. In addition, C3H mice did produce extensive lung granuloma when BCG CW was first injected subcutaneously and rechallenged intravenously. These results strongly suggest that impairment of antigen presentation, when BCG CW was injected intravenously, caused reduced lung granuloma response in C3H mice.

To study adaptive-differentiation phenomena of T lymphocytes, suppressor T-cell factors (TsF) produced by Ly-2+ splenic T cells from fully allogeneic mouse bone marrow chimeras were analyzed. AKR mice irradiated and reconstituted with B10 marrow cells (B10----AKR chimeras) produced an Ly-2+ TsF after hyperimmunization with sheep erythrocytes. The TsF suppressed primary antibody responses (to sheep erythrocytes) generated with spleen cells of mice of H-2b haplotype but not those of H-2k haplotype. Thus, this suppressor factor was donor-H-2-restricted. The immunoglobulin heavy chain variable region gene (Igh-V)-restricting element was not involved in this form of suppression. Similar results were obtained when TsF from B6----BALB/c and BALB/c----B6 chimeras were analyzed. The TsF from B10----AKR chimeras suppressed responses of B10.A(3R) and B10.A(5R) mice but not those of B10.A(4R). This finding showed that identity between the factor-producing cells and target spleen cells is required on the left-hand side of the E beta locus of the H-2 region and that the putative I-Jb locus is not involved in this form of suppression. The present results support the postulate that post-thymic differentiation in the presence of continued or repeated stimulation with antigen and donor-derived antigen-presenting cells generates donor-H-2-restricted T-cell clones that may predominate within the repertoire of the specific antigen being presented.

Employing a new and reproducible method for allogeneic bone marrow transplantation, two kinds of irradiation chimeras were prepared. A/J mice treated with C3H/He marrow cells, which were designated [C3H leads to A/J], where donor and recipient were matched at left one-half of the H-2 complex showed significant numbers of plaque forming cells (PFC) following primary immunization with SRBC, a T-dependent antigen. In contrast [BALB/c leads to A/J] chimeras where donor and recipient were matched at right one-half of the H-2 were unresponsive to SRBC. These results are quite concordant with our previous observations in which B10 H-2 recombinant mice and AKR were used as bone marrow donor and recipient respectively. The vigorous antibody responses after the second stimulation with SRBC, however, were seen in either [C3H leads to A/J] or [BALB/c leads to A/J] chimeras. Direct PFC responses in [BALB/c leads to A/J] chimeras were slightly higher than those of [C3H leads to A/J] chimeras or normal control mice, while indirect PFC responses in [BALB/c leads to A/J] chimeras were low compared to those of the latter groups of mice. These findings suggest that there might be a delay in initiating the response and switching from IgM to IgG production in the chimeras where donor and recipient differed at the left one-half of the H-2.

Using irradiation bone marrow chimeras which had partial compatibility in H-2 subregions between donor and recipient mice, we found that H-2I matching was sufficient for the chimeras to generate anti-sheep erythrocyte plaque-forming cell (PFC) responses. In such chimeras, T cells appeared to encounter appropriate partner cells bearing the same Ia antigens as those which they had learned to recognize as self in the recipient micro-environment. Furthermore, the PFC number seen in I-A compatible chimeras was only about half of that seen in I-A, I-E compatible chimeras, suggesting the existence of two independent subpopulations of helper T cells. When incompatibility of donor and recipient mice existed on the left side of the H-2I region, the responses were very weak. However, even in such chimeras, marked responses were observed for both IgM and IgG type PFC following a sufficient period after immunization. This observation appears to indicate the existence of a minor subpopulation of helper T cells which can expand and interact effectively with antigen presenting cells of donor type.

Using irradiation bone marrow chimeras to analyze restriction specificity of helper T cells, we found that recipient H-2 type dictated the H-2 type which the T cells recognize as self (adaptive differentiation). T cells from (H-2b----H-2k) chimeras cooperate with non-T cells bearing Iak to generate a vigorous PFC response to sheep erythrocytes (SRBC) in vitro, but not with genetically identical H-2b cells. However, when T cells from the chimeras and H-2b non-T cells were adoptively transferred into irradiated (donor X recipient) F1 mice with SRBC, marked responses were seen in recipient spleens where radio-resistant F1 macrophages might exist and act as antigen presenting cells (APC). From these in vitro and in vivo observations, we considered that in the primary antibody response to a T dependent antigen such as SRBC, only T cell-macrophage (APC) matching is required. In contrast, when T cells from H-2 incompatible chimeras which had been primed with SRBC in vivo were analyzed in vitro, these cells cooperated also with H-2b non-T cells. These findings indicate that there may be two separate stages of T cell differentiation during which the self restriction specificity is acquired: one appears to be responsive to intrathymic influences and is not associated with antigenic stimuli, and the other shows signs of being responsive to post-thymic stimuli and of involving antigenic presentation. Moreover, the latter appears to utilize the influence of donor type macrophages.

The present study was performed to determine whether H-2 matching is required for full cytotoxic T lymphocyte (CTL) responses to allo-H-2 antigens in allogeneic bone marrow chimeric mice. A number of irradiated, bone marrow-reconstituted chimeras constructed from various combinations of marrow cells from B10 H-2 recombinant strains and AKR recipient mice were prepared. Spleen cells obtained from such chimeras and normal control mice were activated in vitro by culturing them with irradiated stimulator cells. It was shown that spleen cells from [4R----AKR], [(4R X 3R)F1----AKR] or [AQR----AKR] chimeras, which were histocompatible on the left hand-side of the H-21 subregion between donor and recipient mice, generated greater CTL activities than those that were seen with spleen cells of [3R----AKR] or [5R----AKR] chimeras, which were histoincompatible in this region. We were unable to demonstrate suppressor cell activity of the spleen cells of [3R----AKR] chimeras cultured with stimulator cells. Although spleen cells from [3R----AKR] chimeras showed substantial proliferative responses to stimulator cells (MLR) and to Con A and LPS, IL2 activities of supernatants from Con A-activated spleen cells (Con A SN) of the chimeras were significantly lower than those of [4R----AKR] or [(4R X 3R)F1----AKR] chimeras. Furthermore, vigorous CTL activities were obtained with either spleen cells or thymocytes from [3R----AKR] chimeras when rat Con A SN was added to the MLR cultures. These observations suggest that the numbers of precursor CTLs in the cells from [3R----AKR] chimeras are at the same level as those of [(4R X 3R)F1----AKR] or normal mice and that the low CTL activities generated by spleen cells of [3R----AKR] chimeras compared to H-2I-matched chimeras are due in large measure to deficiency in IL2 production by the splenic T cells of the [3R----AKR] chimeras.

In the present investigation, the incidence, day of onset and severity of type II collagen (IIC)-induced polyarthritis (CA) in allogeneic bone marrow chimaeras were compared. These chimaeras were prepared by using reciprocal combinations between DBA/1J (H-2q, Igh-1c, Hc1), which are highly susceptible to CA, and SWR/J (H-2q, Igh-1c, Hc0), which are CA resistant, strains of mice. The four kinds of chimaeras, [SWR----DBA/1], [DBA/1----DBA/1], [DBA/1----SWR] and [SWR----SWR], were shown to be full chimaeras. [SWR----DBA/1] and [DBA/1----DBA/1] chimaeras showed serum C5 antigens and most of these mice developed CA, even though severity of CA in [SWR----DBA/1] chimaeras was less than that in [DBA/1----DBA/1] syngeneic chimaeras. By contrast, [DBA/1----SWR] and [SWR----SWR] chimaeras completely lacked serum C5 and did not develop CA at all. However, most of these chimaeras produced considerable total IgG and IgG2a antibodies to IIC in the sera after immunization with the antigens, although differences in the serum levels of IgG2a antibodies were seen between [SWR----DBA/1] and [DBA/1----SWR] allogeneic chimaeras. The present results demonstrate directly a crucial role of complement cascade in the induction and development of CA and reveal that lymphoid cells of SWR mice potentially have the ability to develop CA. Differences in severity of the CA observed in some of these chimaeras, however, could not be readily explained by differences in C5 concentrations alone.

A monoclonal antibody, 1B7, which was established by immunizing C57BL/10 mice with splenocytes from B10.BR, was investigated by serological, immunochemical and functional analyses in mouse, rat, guinea pig and human systems. 1B7 recognized a polymorphic determinant on class II antigens in the mouse system. In the rat system, however, this antibody appeared to recognize a monomorphic epitope shared by all RT-1 haplotypes. 1B7 showed no reactivity in the human and guinea pig strains tested.

We have ascertained previously from a study of fully allogeneic irradiation chimeras in mice that the H-2 restriction of the suppressor factor (Ly-2 T suppressor factor) is determined by the post-thymic environment protected by the donor cells, rather than by the thymic environment of the recipient. In the present study, we analyzed differentiation influences that determine the Igh restriction specificities of the suppressor inducer T cell factor(s) (TsiF) that are produced by Ly-1+ splenic T cells in fully allogeneic bone marrow chimeras in mice. AKR mice that had been lethally irradiated and reconstituted with B10 marrow cells, [B10----AKR] chimeras, produced Ly-1 TsiF after hyper-immunization with sheep erythrocytes (SRBC) which suppressed antigen--specifically the primary antibody responses to SRBC that were generated in cells of the same Igh-Vb haplotype of donor strain and not those generated in cells of the recipient Igh-Va type. Similar results were obtained when Ly-1 TsiF from [B6----BALB/c] and [BALB/c----B6] chimeras were analyzed. Furthermore, the Ly-1 TsiF from [BALB/c----B6] chimeras suppressed the primary antibody responses of both BALB/c [H-2d, Igh-Va, Igh-Ca] and BAB-14 (H-2d, Igh-Va, Igh-Cb), but not those of CAL-20 (H-2d, Igh-Vd, Igh-Cd). These results demonstrate clearly that the Ly-1 TsiF from allogeneic bone marrow chimeras are donor Igh-V-restricted and are not influenced by the recipient micro-environment, presumably that provided by the thymuses of the recipient mice.