Identification of an in vivo CD4+ T cell-mediated response to polymorphic membrane proteins of Chlamydia pneumoniae during experimental infection.
Chlamydia pneumoniae is an obligate intracellular bacterium that causes upper and lower respiratory tract infection in humans. C. pneumoniae harbors the polymorphic membrane protein (Pmp) family with 21 different proteins with a molecular mass around 100 kDa. The Pmps are species-specific, abundant and, together with major outer membrane protein and outer membrane protein 2, the dominant proteins in the C. pneumoniae outer membrane complex. Nevertheless, it is unknown whether Pmps are recognized by the cell-mediated immune response. To address this issue, C57BL/6J mice were infected intranasally with C. pneumoniae and the immune response to primary infection was investigated. We demonstrate, as expected, that the primary response is of the Th1 type by IgG2a- and IgG1-specific sELISA (Medac) on serum. In vivo-primed spleen lymphocytes were found to be reactive to Pmp8, Pmp20 and Pmp21 in an interferon-gamma ELISpot assay. The responses were shown to be mediated by CD4(+) T cells. To our knowledge, this is the first identification of antigens recognized by CD4(+) T cells during murine C. pneumoniae infection.
Loke Diagnostics ApS, Science Park Aarhus, Gustav Wiedsvej 10C, DK-8000 Aarhus C, Denmark. mygind@biobase.dk
Tina
T
Mygind
Brian
B
Vandahl
Anna Sofie
AS
Pedersen
Gunna
G
Christiansen
Per
P
Höllsberg
Svend
S
Birkelund
D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D023521:Chlamydophila Infections / Q000276:immunology*; D016993:Chlamydophila pneumoniae / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D016680:Genome, Bacterial; D051379:Mice; D008807:Mice, Inbred BALB C
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins