Functional T cells in rabbits gut mucosal lymphocytes

Lymphocytes of the intestinal mucosa of chickens

Examination, by light and electron microscopy, of the morphology and the staining properties of intraepithelial lymphocytes from the intestine of the chicken revealed a population of lymphoid cells, of which a proportion (up to 20%) is granulated. The majority of cells were immunoreactive with anti-T cell serum and can therefore be considered to be related to T-lymphocytes, but they did not proliferate when cultured with phytohaemagglutinin. The granulated cells were identical to those previously designated globule-containing leukocytes, but were distinct from mast cells in their morphology, staining reactions and the stability of the granules in different fixatives and buffers.

Intraepithelial, lamina propria and Peyer's patch lymphocytes of the rat small intestine: isolation and characterization in terms of immunoglobulin markers and receptors for monoclonal antibodies

Methods have been determined for the isolation, purification and subsequent characterization of separate populations of rat intestinal lymphoid cells, namely intraepithelial (IEL), lamina propria (LPL) and Peyer's patch lymphocytes (PPL). Dissociation of the epithelium from the basement membrane with subsequent release of IEL was achieved by citrate buffer incubation followed by vortex agitation. LPL were released from the remaining tissue by scraping, and PPL were similarly obtained. Some preparations of lamina propria were further subjected to collagenase digestion. After filtration and density gradient centrifugation, average yields of 220 x 10(4) IEL, 54 x 10(4) LPL and 220 x 10(4) PPL per gram of gut were obtained. Immunofluorescence characterization demonstrated that cells bearing the MRC OX8 (T-suppressor) marker predominated in IE1 (73%) and were present in lower concentrations in LPL (26%) and PPL (6%). Cells with the W3/25 (T-helper) marker accounted for a small proportion of each of the lymphocyte preparations. IE1 were unusual in containing a population of cells which were negative for the W3/13 marker for T cells, but were MRC OX8 positive. B lymphocytes were present in PPL (55%) and LPL (31%), but were virtually absent in IEL (less than 1%). Few plasma cells were observed. The techniques described will allow functional investigations to be made and lead to a better understanding of mucosal immunity.

Gut mucosal lymphocytes in inflammatory bowel disease: isolation and preliminary functional characterization

We have developed an enzymatic technique for isolating human intestinal mucosal lymphoid cells. This method was found to be superior to mechanical methods in regard to cell yield and survival. It is based on treating mucosa with serum-free solutions containing collagenase and deoxyribonuclease, followed by isolating the lymphoid cells through centrifugation steps involving fetal calf serum and ficoll-hypaque. Exposure of peripheral blood lymphocytes to the components of the enzymatic solution did not appreciably alter their uptake of tritiated thymidine in the presence or absence of mitogens. Application of the method to derive lymphoid cells from Crohn's disease, ulcerative colitis, and normal intestinal mucosa has shown that gut mucosal lymphocytes from inflammatory bowel disease (1) exceed the number of those from normal mucosa by a factor of 3 to 5; (2) show different degrees of tritiated thymidine uptake, spontaneously and in response to mitogens, depending upon the time they are harvested during the dissociation process; (3) are better stimulators than responders in the allogeneic mixed lymphocyte reaction; (4) generate suppressor cell activity comparable to that of peripheral blood lymphocytes; (5) cannot, in contrast to peripheral blood lymphocytes, generate antibody-dependent cell mediated cytotoxicity; and (6) produce an average of 5 times more IgM than equal numbers of peripheral blood lymphocytes.

Immediate IgA precursor cells in rabbit intestinal lamina propria

Immunofluorscence studies have shown that injection of lymphocytes from either the intestinal lamina propria (LP) or from the Peyer's patches (PP) into irradiated (1000-1250 rad) allogeneic rabbits leads to the differentiation and proliferation of IgA containing cells in the spleen, mesenteric lymph node (MLN) and intestine by day 6 and to a lesser extent by day 4. In contrast, few IgA containing cells were seen in irradiated animals not given lymphocytes or given popliteal lymph node cells. Transfer of PP lymphocytes resulted in statistically greater numbers of IgA containing cells in the recipient MLN or spleen than did transfer of LP lymphocytes. In the PP of recipient rabbits given either LP or PP lymphocytes, intercellular IgA was abundant and more IgA containing cells were seen near the PP than in sites distant from PP. These results show that IgA precursor cells are present in the intestinal LP as well as in the PP. The nature and distribution of the IgA precursor and the characteristics of the IgA repopulation are discussed.

Colostral cell-mediated immunity and the concept of a common secretory immune system

Historically colostrum and milk have been thought to confer immunity on the neonate only by virtue of their immunoglobulin content. Recently we have observed that colostrum also contains viable T lymphocytes capable of expressing cell-mediated immunity in vitro and have employed techniques of lymphocyte culture to elucidate the local nature of mammary tissue immunity at the T-cell level. The results indicate that the activity of colostral lymphocytes appears not to represent the total immunological experience of the mother but that they may contain reactive clones beneficial for the suckling. Colostral immunity appears to depend upon sensitizing events within the intestine and respiratory tract, followed by the migration of lymphoid precursors to the breast, suggesting a relationship between the expression of immunity at various secretory surfaces.