Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/19/1998
Publication Date: N/A
Technical Abstract: Development of mutant mice with genetic deletions such as the T cell receptor (TCR) ab and gd chains have enabled researchers to investigate the importance of T lymphocyte subsets in resistance to infection with intracellular pathogens such as M. paratuberculosis (paratb), the causative agent of a chronic inflammatory enteritis in ruminants. Weanling TCR-a-deficient (def.), TCR-d-def., and C57BL/6 control mice (5 6 wks of age), purchased from Jackson Laboratories, were inoculated IP with 10*8 CFU/ml of M. paratb, strains 19698 and Ben. Groups of mice within each strain were euthanized at 3 and 6 mos. post-inoculation. Spleen, liver, ileal sections, and regional lymph nodes were excised from the peritoneal cavity and processed for culture on Herrold's egg yolk medium containing mycobactin J or sectioned for histological examination. After 3 mos. of infection, TCR-a-def. mice had higher levels of tissue colonization compared to TCR-d-def. or control mice, regardless of strain used. Infection was confined to the spleen and liver in TCR-d-def. and control mice but extended to all tissues for TCR-a-def. mice challenged with strain Ben. The pattern of results was similar after 6 mos. of infection, however, infection was further exacerbated in TCR-a-def. mice compared to their 3-month infection counterparts. These results suggest that ab T cells are more critical for resistance to infection with M. paratb than gd T cells.