Distribution of immune cells in the female reproductive tract in uninfected and FIV infected cats

Cell-free and cell-associated FIV effectively cross the mucosa of the felin e female reproductive tract. To identify possible cellular targets of FIV a nd to characterize changes in mucosal immunity after infection, we examined the types and numbers of immune cells residing in the reproductive tracts of control and intravaginally FIV-infected cats. Sections of the vestibule, vagina, cervix, uterus, and ovaries, were examined by immunohistochemistry for CD4(+) and CD8(+) T lymphocytes, CD22(+) B lymphocytes, CD1a(+) dendri tic cells, and CD14(+) macrophages. The reproductive tract of uninfected ca ts contained substantial numbers of CD8(+) T lymphocytes, CD4(+) T lymphocy tes and macrophages, as well as moderate numbers of CD1a(+) dendritic cells , and few B lymphocytes. The most prominent change between FIV- and FIV+ ca ts was a marked decrease in the concentration of CD4(+) T lymphocytes resul ting in inverted CD4(+):CD8(+) ratios throughout the reproductive tract of infected cats. There was also a trend towards increasing numbers of CD1a(+) dendritic cells in the intravaginally-infected FIV+ cats, and decreasing n umbers of macrophages and CD22(+) B lymphocytes. This study indicates that similar to the peripheral immune system, FIV infection is associated with C D4(+) cell loss and reduced CD4(+):CD8(+) ratios in the female reproductive mucosal tissue. (C) 2001 Elsevier Science B.V. All rights reserved.