The immunoregulatory role of Fcy receptor-bearing T lymphocytes (Ty) in experimental pulmonary tuberculosis /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1990.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | A guinea pig model of pulmonary tuberculosis was used to investigate the regulatory role of thymus-dependent (T) lymphocytes expressing receptors for the Fc portion of immunoglobulin G (IgG). This FcR+ T lymphocyte subset (Tγ) was recognized by its ability to rosette with IgG-coated bovine erythrocytes, or by its adherence to a monoclonal anti-Fc (subscript γ2)R antibody on plastic dishes. The extremes of the clinical and immunological spectrum of tuberculosis were recreated in the guinea pig by vaccination with Mycobacterium bovis BCG (reactive extreme) or dietary protein deprivation (unreactive extreme), followed by low dose, respiratory challenge with virulent M. tuberculosis H37Rv. Protein malnourished guinea pigs were hyporesponsive to PPD in vivo and in vitro, and were not as protected by prior BCG vaccination against pulmonary challenge. The proportion of Tγ cells decreased temporarily, but significantly, as the virulent infection developed. Malnourished animals possessed significantly fewer splenic T (subscript γ) cells than control animals. Studies of malnutrition alone, respiratory infection alone, or the two conditions combined indicated that a significant impact on T(subscript γ) cell levels was observed in all tissues examined only when the virulent infection was superimposed upon pre-existing protein deprivation. The effect of malnutrition alone or infection alone was exerted in a tissue-dependent fashion. Vaccinated and/or infected guinea pigs responded serologically to PPD and two recombinant mycobacterial heat shock proteins, M. bovis hsp 65 and M. tuberculosis hsp 70. These same antigens triggered significant proliferative responses, especially in blood lymphocytes. The lymphoproliferation induced by mycobacterial hsp antigens was significantly impaired in cells from protein-deprived guinea pigs. Selective removal of T (subscript γ) cells significantly enhanced the proliferation of T(subscript non- γ) cells in vitro when cultured with PPD, hsp 65 or hsp 70. The suppressive effect of Tγ cells was most striking in the peripheral blood, but was also detected in splenocyte populations. The Tγ cells themselves appeared to be essentially non-proliferative to mycobacterial antigens in vitro. Taken together, these data support the hypothesis that Tγ cells are responsible, in part, for regulating the range of antigen-specific cellular responses which characterize the clinical spectrum of pulmonary tuberculosis. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Medical sciences." |
| Physical Description: | xi, 94 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |