Suppressor T cells and host resistance to tye 111 pneumococcus after treatment with antilymphocyte serum

CD8+ Tregs in lupus, autoimmunity, and beyond

While CD4(+)CD25(high) regulatory T cells (Tregs) have garnered much attention for their role in the maintenance of immune homeostasis, recent findings have shown that subsets of CD8(+) T cells (CD8(+) Tregs) display immunoregulatory functions as well. Both CD4(+) Tregs and CD8(+) Tregs appear impaired in number and/or function in several autoimmune diseases and in experimental animal models of autoimmunity, suggesting the possibility of immunotherapeutic targeting of these cells for improved management of autoimmune conditions. Our group has developed a strategy to induce CD8(+) Tregs in autoimmune mice through the use of a tolerogenic self-peptide, and new information has been gained on the phenotype, function and role of induced CD8(+) Tregs in autoimmunity. Here we present an overview of the role and mechanisms of action of CD8(+) Tregs in autoimmunity, with a special focus on lupus. We also discuss the potential role of CD8(+) Tregs in other diseases, including chronic infection and cancer.

Induction of immune tolerance by activation of CD8+ T suppressor/regulatory cells in lupus-prone mice

Multiple CD8(+) suppressive T cell (Ts) subtypes are now recognized as essential regulators of the immune system that prevent autoimmunity through secretion of multiple cytokines and the subsequent inhibition of effector lymphocyte function. CD8(+) Ts are an exciting area of study because of the possible therapeutic implications of inducing suppressive cells that are able to subdue or anergize autoimmune manifestations. Current research in systemic lupus erythematosus (SLE), a disease in which most effective therapies are widely immunosuppressive, is often focused on novel and highly targeted ways in which to treat this multiorgan disease. CD8(+) Ts have been impaired in human and murine SLE. Our group and others have utilized tolerogenic peptides to induce and study CD8(+) Ts to understand their function, as well as investigate a possible new SLE therapy. This review will discuss the similarities and differences in CD8(+) Ts subsets, the concept of tolerance as a therapy, and the current understanding of CD8(+) Ts in mouse SLE models.

Case report. Disseminated sporotrichosis presenting as sarcoidosis: electron microscopic and immunologic studies

A 50-year-old black man with constitutional symptoms, cutaneous nodules, and bilateral hilar adenopathy was found to have non-caseating granulomata on bronchial biopsy. He was treated with corticosteroids for sarcoidosis. Within five months he was found to have disseminated sporotrichosis. Electron microscopy revealed mycelial forms of S. schenckii in superficial lesions and yeast forms from deep tissue sites: no novel forms were seen. Blood mononuclear cell studies revealed hyperactive suppressor cells with respect to non-specific T cell targets and the antigen specific target. Examination of the initial biopsy material after digestion with diastase before PAS staining revealed budding yeast consistent with S. schenckii. This case emphasizes the need for careful histopathologic examination of clinical material before a diagnosis of sarcoidosis is made, and reveals an immunologic abnormality which may account for the patient's anergic state and susceptibility to S. schenckii infection.

Modification of antibody response to type III pneumopolysaccharide by route of injection of pertussis vaccine

Pertussis vaccine (PV) or diphtheria toxoid-PV-tetanus toxoid (DPT) altered the antibody response of BALB/c female mice to type III pneumococcal polysaccharide antigen (S3). The key factor affecting the magnitude of the response to S3 was the route of injection of PV or DPT, whereas the route of injection of S3 was not crucial. Subcutaneous injections of DPT augmented the antibody response to low, optimal, and tolerogenic (high) doses of S3 injected either subcutaneously or intraperitoneally. This enhancement was persistent and was observed both when S3 and DPT were mixed and injected subcutaneously and when S3 and DPT were injected concurrently at separate subcutaneous sites. When either PV or DPT was injected intraperitoneally, the antibody response to subcutaneously or intraperitoneally injected S3 was significantly decreased. These experiments demonstrate a dichotomy of effect dependent on the route of administration of PV. Most studies in mice utilizing PV employ the intraperitoneal injection route, and it is important to consider whether PV treatment by this route may have unique effects. Our data suggest that intraperitoneal injection of PV suppresses B cells, possibly by influencing regulatory cell function.

Complications and immunological studies of measles virus infection in antithymocyte-treated hamsters

A study was done to investigate possible late central nervous system (CNS) complications of latent measles infection in hamsters. Signs of CNS disease, consisting of myoclonus and paralysis, occurred in some weanling hamsters inoculated intraperitoneally at 3 or 9 days of age with antithymocyte serum (ATS) and measles virus, but no late complications in adult life attributable to measles virus were seen. A single series of ATS injections plus an injection of measles virus resulted in sustained antibody formation postulated due to establishment of a latent viral infection, whereas similar treatment with normal rabbit serum plus virus caused no or minimal antibody response. The majority of hamsters receiving ATS as newborns and ATS plus virus as weanlings also did not produce antibody. This differential effect of ATS may be due to combined elimination of suppressor and helper cells in the latter ATS-treated group and of suppressor cells only in the former ATS-treated group. Cellular immunity could not be evaluated since lymphocytes from inoculated and uninoculated hamsters released equal and variable amounts of 51Cr for both infected and noninfected labeled, allogeneic hamster target cells.