Direct Detection Of T Cells May Characterize Immune Response.(to Chlamydia trachomatis)

2001 MAR 7 - (NewsRx.com & NewsRx.net) --

by Michelle Marble, staff medical writer -- Direct detection of specific cells may help characterize immune responses to Chlamydia trachomatis.

"We recently identified human leukocyte antigen (HLA) class I-presented epitopes in the major outer membrane protein (MOMP) of Chlamydia trachomatis that elicit cytotoxic T lymphocytes (CTL) responses in human genital tract infections," said S.K. Kim and colleagues, Yale University. "T cells possessing cytolytic activities specific for these epitopes could be detected following in vitro stimulation of peripheral blood CD8(+) T cells with peptides."

Using ex vivo tetramer analysis, the researchers observed MOMP-specific T cells in the peripheral blood of infected individuals at significant frequencies (0.01-0.20% of CD8(+) T cells). After in vitro stimulation of the peripheral blood with peptides, they observed that the frequency of MOMP peptide-specific T cells increased up to 2.34% of CD8(+) T cells in bulk cultures.

In contrast, Kim et al. found that HLA-A2/MOMP tetramer-binding T cells were almost undetectable in the peripheral blood from uninfected individuals, either ex vivo or after three weeks of in vitro peptide stimulation of their T cells.

Their data showed that magnetically sorted, tetramer-bound T cells could specifically lyse peptide-pulsed targets as well as C. trachomatis-infected epithelial cells. This was ...