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The present study is an attempt to produce xenogeneic anti-idiotype antibodies (Id) against mouse anti-H2 antibodies. The purpose is to obtain such anti-Id antibodies with reactivity against both B and T cells in quantities which will allow thorough investigation of the biochemical nature of the T cell receptor for alloantigen. Data are presented from experiments performed with an antiserum 5936 which was obtained after immunization with C57B1/6 anti-CBA antibodies.

The present study describes the qualitative reactions of a xenogeneic anti-idiotype (Id) antiserum produced in a mouse-gamma-globulin-tolerant rabbit (5,936) against B6 anti-CBA IgG antibodies. The results showed that such an anti-Id antiserum reacts specifically against anti-H-2k antibodies and against H-2k alloantigen-activated T cells from the following pairs of congenic mice: B10 (H-2b) and B10.D2 (H-2d); and A.BY (H-2b) and A.SW (H-2s), but not against C3H.SW (H-2b) and C3H.OH (H-2o); and BALB/b (H-2b) and BALB/c (H-2d). CB 20 (BALB/c mice with the Ig-1b allotype) anti-CBA T blasts also express idiotypic determinants that react with rabbit 5,936 antiserum. Thus, positive reactions are obtained between rabbit 5,936 anti-Id antiserum and anti-H-2k IgG preparations and T blasts from mice carrying the Ig-1b or Ig-1e allotype, but not from mice carrying the Ig-1a allotype. These reactions are qualitatively independent of the H-2 genotype of the Id-producing mice. Such a finding strongly suggests that the Id-bearing receptor molecules on mouse T cells are coded for by genes that are associated with the Ig heavy-chain-linkage group and not to the mouse histocompatibility complex. Furthermore, the anti-Id antibodies studied react preferentially against anti-H-2k antibodies or T cells with specificity toward the IAk-region-associated serological specificities. Thus, genes associated with the Ig heavy-chain-linkage group seem to be structural genes for at least T-cell receptors with specificity for IA-region-coded membrane antigens.

Immune guinea pig lymph node cells were fractionated on Ig anti-Ig or HSA anti-HSA affinity columns or on plastic surface in medium containing carbonyl iron. These techniques selectively removed B lymphocytes, K lymphocytes or adherent cells. The residual cells (Fc receptor-negative T lymphocytes) responded to soluble antigen in vitro in the same way or even better compared with nonfractionated cells. In addition, there was no indication that antigen-antibody complexes were superior to antigen in triggering lymph node cells or purified lymph code T lymphocytes into DNA synthesis. The results obtained suggested that memory T lymphocytes can be stimulated by antigen autonomously.

Lethally irradiated mice injected with syngeneic thymocytes and immunized with protein antigens develop specific helper T cells. If injected with semiallogeneic thymocytes, such mice generate H-2 antigen-specific cytotoxic T cells. Most spleen cells from these chimeric mice possess Fc receptors. The present results demonstrate that the development of Fc-receptor-bearing cells in thymocyte-injected irradiation chimeras seemingly is due to the physiological conditions in the mice rather than to the specific immunization. As a corollary, both helper T cells and cytotoxic T cells did not have Fc receptors, at least not in their effector state. Thus, Fc receptors on T cells would seem irrelevant to their immune function.

Naturally occurring suppressor cells of the in vitro mixed leukocyte culture reaction and of in vivo graft-vs.-host disease have been identified in the spleens of neonatal mice (1) and of adult mice recovering from total lymphoid irradiation (2), whole-body irradiation (3), and syngeneic marrow transplantation (4), or cyclophosphamide therapy (5). Using both positive and negative selection procedures, the suppressors were reported to be null lymphocytes that did not express mature macrophage surface markers, nor differentiate into mature macrophages in vitro, nor demonstrate natural killer (NK) activity (1). Subsequently, cloned lines of these natural suppressor (NS) cells were derived from either adult mice given total lymphoid irradiation (TLI) (2) or from neonates (6). The cloned NS cell lines expressed a surface phenotype (2, 6) similar to that reported previously for cloned NK cells (Thy-1(+), asialo-GM1(+), Ig(-), Lyt-1(-), Lyt-2(-), Ia(-), MAC-1(-)) (7-9). However, the NS cells did not show NK activity in the standard assay with YAC-1 target cells. The cloned NS lines suppressed the proliferation of responder cells and the generation of cytolytic cells in the mixed leukocyte reaction (MLR), and suppressed lethal graft-vs.-host disease in vivo (10, 11). In view of the unusual function and surface phenotype of the cells, the lineage of these cells remained unclear. To determine the lineage of the cloned NS cells, we searched for expression and rearrangement of the α and β chain genes of the T cell antigen receptor, as well as that of the γ chain gene. Studies of the phenotypically similar NK cell yielded conflicting results. Thus, cloned lines of murine NK cells were reported to have rearrangements of the β chain genes, and to express mRNA for all three chains (12). In contrast, freshly purified rat or human large granular lymphocytes (LGL) were shown to express only the 1.0 kb mRNA species of the β chain gene (13), indicative of D-J joining (14). Thus, some but not all cells with NK function express the T cell receptor and are members of the T cell lineage. The current report shows that the NS lines express full-length mRNA transcripts for the a and β chain of the T cell receptor, as well as the γ chain gene.

Injection of thymocytes into lethally irradiated mice generates in the spleen of the hosts a lymphoid cell population which consists mainly of T lymphocytes (1–5) This procedure has been used frequently in studies on the induction of T lymphocyte effector functions. Thus, the injection of parental thymocytes into 800 R irradiated F1 hybrid mice produces a cytotoxic T lymphocyte population specific for the H-2 antigens possessed by the other parent. The induction and expression of this particular T lymphocyte effector function have been shown not to depend on Fc receptor, C3′ receptor or membrane immunoglobulin (Ig) positive cells (2, 4). A majority of spleen cells from irradiated F1 hybrid mice injected with parental thymocytes acquire Fc receptors (3). Since, as stated above, cytotoxic T lymphocytes did not carry Fc receptors, we looked for Fc receptors (as measured by the EA-RFC assay; E = sheep erythrocytes, A = CBA×Balb/c anti-SRBC 7S antibodies, RFC = rosette forming cells (4)) on helper T lymphocytes induced by injecting syngeneic thymocytes into 800 R irradiated F1 hybrid mice together with the protein antigens: human serum albumin (HSA) or ovalbumin (OA), emulsified in complete Freund’s adjuvant (CFA). In addition we investigated the development of Fc receptor bearing cells in the spleens of 800 R irradiated F1 hybrid mice injected with 1) saline, 2) syngeneic thymocytes, 3) syngeneic thymocytes and protein antigen in CFA, or 4) parental thymocytes. This was done in order to determine whether the Fc receptor bearing cells were of host origin or derived from the thymocyte inoculum and whether the Fc receptor bearing cells developed as a consequence of immunization.

The survival of peritoneal exudate macrophages after 3 to 10 days in culture was examined by measuring the numbers of phagocytes per culture. This was determined by letting the cultured cells phagocytize Latex particles. The number of Latex particle-containing cells was taken as a measure of the survival of phagocytes. It was found that one tenth of the cells judged by light microscopy as macrophage-like survived the culture period. Thus, the calculated plating factor of 9.3 was used to estimate the actual number of macrophages in suspensions of spleen, lymph node or thymus cells by culturing these cells and subsequently counting Latex particle-containing cells. In addition, the acridine orange technique was used to determine actual numbers of macrophages in freshly prepared cell suspensions of lymphoid organs. Latex studies on spleen and thymus cells gave results correlating well with data obtained by the acridine orange technique. By contrast, many more acridine orange positive cells than phago-cytizing cells were found when lymph node cells were cultured.

A total of 42 EEGs from five patients with subacute sclerosing panencephalitis were studied. Periodic complexes were noticed in 35 (83%) of these. The interval between the complexes shortened in all patients with progression of the illness. The gradual EEG changes may reflect the increasing number of infected cells as well as an on-going accumulation of immature virus structures. The records without complexes were either from the early onset (one record) or terminal stage (six records).

The present experiments were carried out in order to answer the question whether the precursor T cells of cytotoxic T lymphocytes (PCTL) are Fc receptor positive (FcR+), Fc receptor negative (FcR-), or both. The data show that cytotoxic T lymphocytes (CTL) can be generated in vitro from both FcR+ and FcR- PCTL. Furthermore, we investigated if the function of FcR+ and FcR- CTL differed in the allograft response in vitro. Qualitatively, FcR- PCTL differentiate into FcR- CTL only, whereas FcR+ PCTL differentiate into both FcR+ and FcR- CTL. However, quantitatively, CTL generated from FcR- PCTL display a higher T cell mediated cytotoxicity than CTL generated from FcR+ PCTL. Mixing experiments indicate that FcR+ T cells regulate the differentiation of FcR- PCTL into CTL. These conclusions hold true for PCTL in both normal and memory responder cell populations.

The present report deals with our attempts to characterize the potent stimulator cell(s) that induce Fc receptor (FcR)-negative T lymphocytes to differentiate into cytotoxic T lymphocytes in vitro. We found two categories of such cells: [1] resting B cells, FcR+ T cells, and macrophages and [2] T cells either activated in 800-R-irradiated mice against H-2 antigens or M-locus antigens or activated in vitro by concanavalin A. The distinction between potent and weak stimulator cells is discussed in relation to the surface antigenic markers and the immunological function of these cells.