Repopulation of the gut lamina propria with IgA-containing cells by lymphoid cells isolated from the gut lamina propria

Infectious Diarrhea

Infectious diarrhea constitutes a major source of morbidity and mortality for all age groups. The focus of this article is to identify high risk host and pathogenic risk determinants of enteric infections, discuss pathophysiologic mechanisms for diarrhea, review conventional and upcoming therapeutic managements of bacterial, protozoal or viral-type diarrhea, and describe the integral role of the pharmacist in the overall care of patients having this illness.

Peritoneal cavity CD5 (Bla) B cells: cytokine induced IgA secretion and homing to intestinal lamina propria in SCID mice

The mouse peritoneal cavity contains a unique population of B cells (Bla) with a high IgM/low IgD ratio, CD5+ (Ly1), MAC-1 + phenotype. These cells arise early in ontogeny, utilize a limited repertoire of immunoglobulin V genes, produce polyreactive IgM antibodies and have been implicated as the source of many auto-reactive immunoglobulins. Recent data from chimeric mice suggest that this B cell population also contains the precursors of many IgA plasma cells found in the lamina propria of the small intestine. In the present study we have investigated the potential of this cell population to secrete IgA (and IgG) in response to various cytokines. IL-5 alone, or in combination with IL-2, greatly enhanced secretion of both IgG and IgA. Cytokine-induced IgA secretion resulted from expansion of a subset of CD5 B cells co-expressing sIgA. Adoptive transfer of CD5 B cells while peripheral lymph nodes contained only IgM+ and some IgG+ B cells. Transfer of CD5+ B cells also reconstituted serum IgM, IgG and IgA and IgG, immunoglobulins characteristic of mucosal and anamnestic responses, when cultured in vitro with the appropriate cytokines. These cells also give rise to IgA plasma cells in the intestinal lamina propria following adoptive transfer to SCID mice, further supporting the hypothesis that cells of this lineage may be important in immune responses at mucosal surfaces.

Infectious Gastroenteritis

Infectious gastroenteritis currently constitutes the greatest source of morbidity and mortality among various age groups. Issues of focus for this article include establishing epidemiological determinants of risk for enteric infection, describing host factors that favor survival of the infecting enteric pathogen, defining pathophysiological mechanisms of diarrhea, and reviewing the therapeutic management of bacterial, protozoal, and viral infectious diarrhea.

Characterization of surface markers of bovine gut mucosal leukocytes using monoclonal antibodies

The surface phenotypes of bovine intestinal leukocytes isolated from the intraepithelium (IEL), lamina propria (LPL) and Peyer's patches (PPL) of the small intestinal mucosa of normal adult cows were determined using monoclonal antibodies (mAb) specific to adult bovine peripheral blood leukocytes (PBL). Laser flow cytometric (LFC) analysis demonstrated that IEL contained significantly (P less than 0.1 to 0.02) fewer cells (26%) expressing the pan T cell phenotype in comparison to LPL (38%) and PPL (44%). Similarly, significantly (P less than 0.01 to 0.001) lower numbers of B cells were observed among IEL (10%) compared to LPL (28%) and PPL (33%). While approximately equal numbers of B7A1+ "null" cells (10%) and DH59B+ "Ia+ monocytes/granulocytes" (16.5%) were observed among the three intestinal cell populations, IEL contained significantly (P less than 0.1 to 0.05) lower numbers (19%) of T helper (Th) cells in comparison to LPL (44%) and PPL (38%). In contrast, lymphocytes with the T cytotoxic/suppressor (Tc/s) phenotype were significantly lower (P less than 0.01 to 0.001) among LPL (14.5%) compared to IEL (25%) and PPL (23%). While the numbers of cells expressing class I major histocompatibility complex (MHC) surface antigens (H58A+) were approximately equal among LPL (79%) and PPL (87%), a significant difference (P less than 0.02) was observed between IEL (71%) and PPL. Similarly, while approximately equal numbers of cells expressing the MHC class II surface phenotype were observed among LPL (42%) and PPL (46%), IEL contained significantly (P less than 0.01) fewer (31%) MHC class II cells in comparison to PPL. Enrichment for T cells by plastic adherence and Sephadex G-10/nylon wool fractionation revealed a significant (P less than 0.01) and proportional increase in T lymphocyte subsets expressing pan T, Th and Tc/s phenotypes among the three cell populations. Similarly, enrichment for B cells by the same techniques showed a significant (P less than 0.01) and proportional increase in cells expressing the panB cell phenotype among LPL and PPL. Marked differences in cell size distribution and cell surface density were observed when the three intestinal leukocyte populations were compared by LFC using monoclonal antibodies directed at various cell surface markers. Furthermore, considerable quantitative variations of each cell surface marker were observed among the individual animals tested. The results of this study indicate that bovine IEL, which contain a high percentage of cells (greater than 30%) with no known phenotype are significantly different from LPL and PPL which are phenotypically similar cell populations.(ABSTRACT TRUNCATED AT 400 WORDS)