Activation in vivo of a major antisuppressor T-cell pathway immediately after immunization. I. Its regulation by I-A gene products

2-Carboxyethylgermanium sesquioxide, a synthetic organogermanium compound, as an inducer of contrasuppressor T cells

2-Carboxyethylgermanium sesquioxide (Ge-132), a synthesized organogermanium compound with immunomodulating activities, was shown to be an inducer of anti-suppressor T cells in normal mice. The suppressor cell activity of T6S cells, a clone of burn-induced CD8+ IL-4-producing suppressor T cells, was clearly inhibited when a mixed lymphocyte-tumor cell reaction of the clone was conducted with splenic mononuclear cells from mice treated orally with a 100 mg/kg dose of Ge-132. The activity of anit-suppressor cells was demonstrated in spleens of mice 2 days after treatment with Ge-132 and reached its peak on day 3. The anti-suppressor cells induced by the compound were of a contrasuppressor T cell-linage, because they were characterized as CD4+ CD28+ TCRalpha/beta+ Vicia villosa lectin-adherent T cells. These cells produced IFN-gamma but did not produce IL-2, IL-4, IL-6 or IL-10 in their culture fluids. CD4+ anti-suppressor T cells induced by Ge-132 may be different from other subsets of CD4+ T cells because Th1 and Th2 cells generated in our laboratory did not adhere to Vicia villosa lectin-coated petri dishes, and each produced specific cytokines. Th1 cells produced IFN-gamma and IL-2 while Th2 cells produce IL-4 and IL-10 in vitro. These results suggest that Ge-132 may be useful as an inducer of contrasuppressor T cells in immunocompromised individuals bearing suppressor T cells. To eliminate suppressor T cells from immunocompromised hosts may result in improved resistance from various opportunistic infections.

Glycyrrhizin (20 beta-carboxy-11-oxo-30-norolean-12-en-3 beta-yl-2-O-beta-D-glucopyranuronosyl-alpha-D-glucopyranosiduronic acid) improves the resistance of thermally injured mice to opportunistic infection of herpes simplex virus type 1

The effect of glycyrrhizin (GR) on the resistance of thermally injured mice to opportunistic herpes simplex virus type 1 (HSV) infection was investigated. We have previously reported that the susceptibility of thermally injured mice or normal mice inoculated with T6S cells (a clone of burn-associated CD8+ CD11b+ TCR gamma/delta + type-2 suppressor T cells), to HSV infection was about 100 times greater than it was in normal mice. When thermally injured mice were treated i.p. with a 10 mg/kg dose of GR 2 and 4 days after infection of HSV, the resistance of these mice to HSV was improved to levels observed in normal mice. The adoptive transfer of splenic mononuclear cells (MNC) from normal mice treated with GR (GR-MNC) to thermally injured mice (recipients) resulted in the improved resistance of recipients to HSV infection. Normal mice inoculated with T6S cells and exposed to HSV had an 80% mortality rate, when given GR-MNC they had a 95% survival rate. The suppressor cell activity of T6S cells was clearly counteracted by GR-MNC in vitro in a mixed lymphocyte-tumor cell reaction. The type of cells responsible for anti-suppressor cells in GR-MNC was shown to be a CD4+ CD28+ TCR alpha/beta + Vicia villosa lectin-adherent T cell. These results suggest that GR may reverse the increased susceptibility of thermally injured mice to HSV infection through the induction of CD4+ contrasuppressor T cells.

Effect of a traditional Chinese herbal medicine, kanzo-bushi-to, on the production of interleukin-4 from a clone of burn-associated CD8+ suppressor T cells

Effect of Kanzo-bushi-to (TJS-038), one of the Japanese Kampo medicines originating from traditional Chinese herbal medicine, on the activity of a clone of burn-associated CD8+ suppressor T cells (T6S cells) was investigated. The suppressor cell activity of T6S cells in the mixed lymphocyte-tumor cell reaction (MLTR) was not changed when various concentrations of TJS-038 were added to the MLTR. The suppressor cell activity of T6S cells was greatly inhibited by CD3+ CD4+ CD28+ TCR alpha/beta+ Vicia villosa lectin-adherent cells (TJS cells) purified from spleen cells of mice treated with TJS-038 at an oral dose of 50 mg/kg. The suppressor cell activity of T6S cells was not demonstrated in the MLTR assay when anti-IL-4 monoclonal antibody was added. Also the production of IL-4 from T6S cells was not detected, when they were co-cultured with TJS cells. These results suggest that TJS-038 stimulates the generation of contrasuppressor T cells (TJS cells) that inhibit the suppressor cell activity of T6S cells and the production of IL-4 from T6S cells.

B cell dependent T cell function blocked by perinatal exposure of mice to anti-IgM antibodies

Mice born to mothers deprived of B lymphocytes by their chronic treatment with anti-IgM antibodies (Su/N) do not possess naturally occurring anti-ids (present in sera of normal mice at 2 weeks of age) up to 10 weeks, despite the presence of normal levels of B cells and serum Ig (in these animals). Su/N mice of the same age also lack a T cell subset which together with anti-ids are thought to participate in an antisuppressor regulatory pathway. It is suggested that early development of these T cells may be linked and be dependent on the presence of these anti-ids synthesized early in ontogeny, providing one explanation for a selective T cell deficiency of B cell-deprived mice.

Inhibition of antisuppression by the acute murine graft-versus-host reaction

Profound suppression of both humoral and cell-mediated immunity is a significant systemic effect of graft-versus-host reactions. Although no complete explanation has been advanced for this immunosuppression suppressor cells have been implicated. The data presented in this paper indicate that acute GVH reactions in (C57BL/6J X A/J) F1-hybrid mice induced by the injection of A/J cells severely disrupts the function of the antisuppressor T-cell pathway at both its induction and effector stages. Results show that within 3 weeks of induction of the reaction, Ly1+-T antisuppressor inducer cells lose their ability to generate the serum factor that mediates antisuppression. This factor is normally taken up by and activates Ly2+ T cells which then inhibit suppressor T-cell function. The data also reveal that Ly2+ T cells collected 2 weeks after induction lose their ability to be activated by the antisuppressor factor produced in normal mice. These cells are thus unable to function as antisuppressor effector cells. The uptake of the antisuppressor factor by Ly2+ T cells depends on the expression of Ia antigens on the surface of these cells. Experiments have shown that these antigens are absent from the surface of T cells derived from mice with GVH reactions. This finding may provide an explanation for the inability of these cells to function as antisuppressor effectors. Antisuppression is an important T-cell pathway that is intimately associated with the regulation of immune function. It is possible that the immunosuppression arising in mice with GVH reactions may stem, in part, from unopposed suppressor T-cell activity that results from widespread interference by the reaction with a pathway that normally inhibits suppressor cell activity.

Macrophage T cell interaction. Induction in vitro of a mediator with potent antisuppressor activity

A simple in vitro method is described for the induction of a potent mediator that interferes with suppressor cell function. The mediator consists of three easily identifiable components, Ig, class II determinants and antigen, that form a unique complex similar to, or identical with, the complexes detected in vivo within 3-6 h after immunization. The formation of the antisuppressor mediator in vitro takes place in two steps: the first involves a macrophage-T cell interaction which generates an 'intermediate complex' containing antigen and class II determinants. In the second step the addition of immunochemically purified IgG from normal mouse serum to the macrophage-T cell supernate generates potent antisuppressor activity, which is assayed by the conversion of suppression to immunity. It is suggested that the IgG interacts with the 'intermediate complex' giving rise to the final complex identical to that found in vivo 6 h after immunization. No activity is detected when IgG is added to a supernate of antigen-fed macrophages in the absence of T cells. Furthermore, the T cell plays an additional important role in the formation of the final complexes since it restricts the source of the IgG that will generate the antisuppressor activity. In other words the antisuppressor function is detected only if the IgG matches the donor of the T cell in the Igh locus. The T cell involved in the formation of the complex is the Ly1+ subpopulation. This method should allow elucidation of the genetic, cellular and molecular mechanisms in the activation of this important T cell pathway.

Preferential induction of antigen-specific contrasuppressor T lymphocytes by trinitrophenyl (TNP)-substituted Langerhans cells

We have tested the ability of trinitrophenyl (TNP)-labelled antigen-presenting cells (Langerhans cells (LC) and peritoneal macrophages (M phi)) administered intravenously to induce cells that mediate and regulate contact sensitivity. TNP-M phi fail to induce contrasuppressor cells (Tcs) but activate efferent T suppressor (Ts) cells. However, the activity of immune cells can be recovered after removal of Ly 2 Ts cells. In sharp contrast, TNP-substituted purified LC produced a significant contact sensitivity reaction, which is roughly equivalent to that achieved by skin sensitization with picryl chloride. Immune cells from these animals were relatively resistant to suppression by antigen-specific Ts cells, and we have found that their resistance is due to the presence of Ly 1, Vicia villosa lectin adherent, I-J+ cells. The Tcs cell induced by TNP-LC is indistinguishable by surface markers and function from Tcs cell found in mice injected with antigen-antibody complexes. Both these Tcs cells are capable of protecting immune cells from the effects of suppression by antigen-specific Ts cells if added in the proper sequence. Although they have identical surface phenotypes, it is not known at present whether or not Tcs cells induced by two different antigen presentations are identical. The possible reasons why LC are such potent inducers of contrasuppression are discussed.

T-cell function in B-lymphocyte-deprived mice

Previous work has identified selective defect(s) in T cells in mice deprived of B lymphocytes by the chronic administration of anti-IgM antibody. Experiments described in the present communication revealed that anti-IgM-treated mice do not possess T cells with surface Ia and FcR, and, unlike T cells from normal animals, they also fail to bind these molecules in vitro. Functional assays disclosed that an anti-suppressor pathway which relies on Ia+ donor and acceptor T cells is interrupted in these mice at both levels. These observations may provide an insight to explain the selective failure of some T cells when B lymphocytes have been deleted.

Activation in vivo of a major antisuppressor T-cell pathway immediately after immunization. III. T-cell requirements for its induction

Immunogenic stimuli rapidly induce a potent mediator with antisuppressor activity which represents complexes of Ig and antigen. The formation of the complexes depends on the interaction of two T cells both of which bear the Ly1 phenotype. The two T cells can be separated on the basis of their sensitivity to antilymphocytic serum and dependency on the presence of thymus. T cells bearing I region coded determinants are essential for the formation of the mediator.

Activation in vivo of a major antisuppressor T-cell pathway immediately after immunization. II. T-cell requirements for its expression

Immunogens activate in vivo within 3-6 hr after injection a new and hitherto unrecognized T-cell pathway which interferes with T-cell suppression, therefore called antisuppression. An important soluble mediator with antisuppressor activity is detected in the serum of immunized animals within 3-6 hr. The mediator represents a unique form of complexes of Ig and antigen. The antisuppressor function of the complexes does not represent a direct "neutralizing" effect of the complexes on the effector T suppressor cells. The antisuppressor complexes activate an Ly2+ T cell which, with the interaction of an Ly123+ T cell, blocks completely T-suppressor-cell function. The biological significance of the T antisuppressor pathway is discussed.