Nicholas R. StC. Sinclair

IMMUNOLOGICAL AND PHARMACOLOGICAL MONITORING IN THE CLINICAL USE OF CYCLOSPORIN A

Immunological reactivity to donor antigens and serum concentrations of cyclosporin A were monitored in six patients after renal transplantation. At concentrations of 0.1--1.0 microgram/ml cyclosporin A prevented both donor-specific immune reactivity and clinical rejection during the early post-transplant course. Measurement of cyclosporin A levels and immunological indices allowed individual adjustment of the dosage so as to give excellent early graft function with few adverse effects.

Anti-Donor Immune Responses in Prediction of Transplant Rejection

We assessed various immune responses against donor tissue to determine their value in the diagnosis and prediction of clinical rejection episodes. Twenty-six consecutive clinical renal-transplant recipients were examined. Cell-mediated lymphocytotoxicity preceded and accompanied 41 of 45 rejection episodes (P less than 0.001). Complement-dependent antibody was present in 12 of 15 rejections (P less than 0.002)--four not accompanied by, and eight in association with, cell-mediated lymphocytotoxicity. Mixed lymphocyte reactivity or nonreactivity and inhibition by autologous serum occurred equally often in rejection and quiescence. Lymphocyte-dependent antibody occurred during both rejection episodes and quiescent phases, with a greater frequency during quiescence (P = 0.05). Cell-mediated lymphocytotoxicity was the best predictor of rejection (P less than 0.05). Cell-mediated lymphocytotoxicity was the best predictor of rejection (P less than 0.001), and was more easily suppressed by standard immunosuppressive therapy, than complement-dependent antibody. If specific cell-mediated lymphocytotoxicity, with or without antibody, recurred after rejection therapy, the graft underwent further rejection.

Regulation of the immune response. Xii. Targets for suppressor cell activity in an in vitro cell-mediated immune response.

Abstract Irradiated CBA anti-DBA/2 cells, produced in a CBA anti-DBA/2 mixed lymphocyte culture, inhibited a second in vitro CBA anti-DBA/2 cytotoxic cell response. Increasing the numbers of CBA responder cells in the second culture decreased suppression, whereas increasing the number of irradiated DBA/2 stimulator cells led to a lesser reduction in suppression. Preincubation of irradiated CBA anti-DBA/2 suppressor cells with CBA rcsponder cells gave a twofold greater suppression than preincubation of CBA anti-DBA/2 suppressor cells with stimulator cells. The inhibitory effect of CBA anti-DBA/2 suppressor cells on CBA responder cells was sensitive to alkaline storage whereas neither the interference with DBA/2 stimulator cell immunogenicity nor antistimulator cell cytotoxicity itself was sensitive to storage. The antiresponder mechanism for suppression predominated over the antistimulator effect when all three cell types (responder, stimulator, and suppressor) are put into culture simultaneously. Additional CBA responder cells corrected the defect in suppressed second cultures, caused by CBA anti-DBA/2 suppressor cells, to a greater extent than additional irradiated DBA/2 stimulator cells. We conclude from these experiments that these suppressor cells exert a major effect on responder cells and a minor effect on stimulator cells.

Interference with Fc signals increases an antibody response by T-cell-deprived cultures to a T-dependent antigen

Affinity column purified goat anti-mouse immunoglobulin antibodies specific for the Fc portion of IgG increased an in vitro antibody response to a T-dependent antigen when T cells were limiting. Picogram amounts of specific anti-Fc antibody at culture initiation and nanogram quantities up to 3 days were required to demonstrate this effect. The demonstration of reconstitution by anti-Fc antibodies requires that the cultures be T-cell depleted and stimulated by antigen. These results support the concept that anti-Fc antibody and T cells block endogenously generated negative Fc signals.

Regulation of the immune response: XI. Cell-mediated feedback of an in vitro cell-mediated immune response

Abstract Irradiated CBA anti-DBA/2 cells (106 cells/culture) suppressed the production of effector cells in cultures containing 107 unprimed CBA (responder) and 106 irradiated DBA/2 (stimulator) spleen cells per culture. The suppressive element was cellular and suppression was specific for the stimulating antigen. The suppressive activity resided in the cytotoxic cell population in that both suppressive and cytotoxic activities were found in cells of the same size range, predominantly in T-cells, were produced in response to similar doses of stimulator antigen, and were produced with the same time course following establishment of first sensitization cultures. Eventual suppression correlated with the cytotoxic activity introduced into second sensitization cultures by suppressor cells. The short-term cytotoxic activity and suppressor activity were both highly radioresistant. These studies indicate that the suppressor cells formed in an in vitro mixed lymphocyte culture are cytotoxic to stimulator cells.

Regulation of the immune response. VIII. Characteristics of antibody-mediated suppression of an in vitro cell-mediated immune response.

Abstract Both in vitro sensitization and in vitro expression of a cell-mediated CBA/H anti-DBA/2 response are suppressed by antibody directed against the stimulator or target DBA/2 cells, respectively. Induction of cytotoxicity and the suppression of sensitization or effector phases of the in vitro cell-mediated immune response by antibody are immunologically specific. Specific suppression by antibody-containing serum is (i) highly dependent on the number of stimulating cells used for sensitization, (ii) most marked when antibody is given at the initiation of the sensitization cultures, (iii) more effective in inhibiting the sensitization phase than the effector phase, (iv) interfered with by absorption with cells which contain stimulating or target cell antigens, (v) limited to the 7S fraction of antibody-containing serums, (vi) not markedly dependent on the Fc portion of antibody, and (vii) not augmented, but inhibited slightly, by the formation of antigen-antibody complexes. The characteristics of suppression by antibody in this in vitro system suggest that inhibition occurs mainly through an antigen-masking mechanism and that antibody feedback inactivation of T cells, equivalent to that of B cells, does not take place. The resistance to antibody feedback of T cells involved in the production of cytotoxic effector cells is similar to the resistance of T cells which operate in helper activities in T cell-dependent antibody responses.

Rheumatoid factor blocks regulatory Fc signals

Immunosuppressed cultures of murine spleen cells, partly deprived of T cells and antigen-stimulated, can be reconstituted to near full activity in their antibody-forming cell response with murine rheumatoid factors (RF). The dose of RF required for recovery of 50% of the reconstitutable immune response was 10-100 ng and reconstitution was blocked by intact murine IgG added to the cultures. IgG subclass specificity of RF was demonstrated; RF specific for IgG2a was more potent than RF specific for IgG1 in reconstituting the response. Synergy was observed between RF added at culture initiation and late-acting B-cell differentiation factors. The greater the degree of T-cell deprivation, the more stringent the conditions needed for reconstitution. Suitable conditions for reconstitution with profound T-cell depletion included the limited reconstitution by specific RF, the synergistic action of RF with late-acting T-cell-replacing supernatants, and multiple additions of a number of RFs to the cultures on Days 0, 1, and 2. RF was also shown to block Fc-dependent immunosuppression by added antigen-antibody complexes. These results are interpreted as favoring the hypothesis put forward previously that the normal production of RF acts to reduce T-cell dependency by preventing negative Fc signal transmission by immune complexes on the B-cell surface. Abnormal production of RF may be a primary destabilizer of the immune responses leading to autoimmunity.

Commentary III: How many signals are enough?

The many signals that control the progress of various immune responses to both foreign and self antigens can be divided into no less than three major groups. The first group is the initial positive stimulus, associated with activation events through antigen receptors and their associated proteins. These signals launch lymphocytes in their response to antigen, either foreign or self. The second group of signals is negative and involves various end products and interactions between cells, all recognizing antigen. These signals are endogenous to the reacting cell, or nearly so (two interacting cells from the same clone, daughter cells, which are in the same locale and bind to the same ligand). The third group (the prevention of end product feedback, involving various forms of antigen presentation, T cell contributions, rheumatoid factor activity, and other mechanisms) is more likely to occur with nonself antigens, which are temporally and spatially more restricted than self antigens. Experimental evidence for this immunological schema is summarized and clarified in its relationship to the Bretscher-Cohn theory of self-nonself recognition and to suppressor cell and idiotype-antiidiotypic theories.

Inhibition of an in vitro cell-mediated response: Further experiments on the cell lineage and target of suppressor cells

Abstract Suppressor cells were generated during a mixed leukocyte reaction. They are heterogeneous in that T cells, cytotoxic cells, Fc-receptor-positive cells, and their opposites all demonstrate suppressive activity. There is a requirement for antigen stimulation for the induction of suppressor cells. Cultures inhibited by the addition of suppressor cells can be reconstituted with responder cells but not with stimulatory cells. These results indicate that a heterogeneous collection of suppressor cells, induced in response to antigen, express their inhibitory activity by depressing the function of or by inactivating specific responder cells.

A Randomized, Double-Blind Comparison Shows the Addition of Oxygenated Glycerol Triesters to Topical Mentholated Cream for the Treatment of Acute Musculoskeletal Pain Demonstrates Incremental Benefit Over Time

Background:  Topical analgesics are important products in the armamentarium for pain relief.