Kinetics of chlamydial antigen processing and presentation to T cells by paraformaldehyde-fixed murine bone marrow-derived macrophages.
Macrophages are potential candidates for antigen presentation to chlamydial-specific CD4+ T cells. We have studied the kinetics of chlamydial antigen processing and presentation by using paraformaldehyde-fixed bone marrow-derived macrophages (BMDM) and splenic T cells isolated from chlamydia-infected mice. BMDM were inoculated with different multiplicities of heat-killed chlamydial elementary bodies, and at different times postingestion, the macrophages were fixed with paraformaldehyde and used as antigen-presenting cells in T-cell proliferation assays. T-cell proliferative responses were shown to be dependent on the chlamydial inoculum size, with a multiplicity of 10 chlamydiae per macrophage producing optimum T-cell proliferation. Temporal experiments showed that peak T-cell proliferative responses occurred between 4 and 12 h postingestion of chlamydiae by BMDM. T cells proliferated strongly to antigen when presented by H-2-matched BMDM but not when presented by H-2-disparate BMDM, demonstrating that T-cell recognition of processed chlamydial antigen was major histocompatibility complex restricted. BMDM inoculated with 10 chlamydiae per cell and fixed at 8 h postinoculation were shown to be as stimulatory to T cells as conventional splenic antigen-presenting cells. Because large numbers of BMDM can be propagated in vitro, and experimental conditions that provide optimum presentation of processed chlamydial antigen to chlamydia-specific CD4+ T cells can be defined, BMDM may be a potentially useful source for the isolation of naturally processed parasite antigen from major histocompatibility complex class II molecules.
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Immunology Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840-2999.
Caldwell
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D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000187:drug effects / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism; D001853:Bone Marrow / Q000187:drug effects / Q000276:immunology; D001854:Bone Marrow Cells; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002692:Chlamydia trachomatis / Q000276:immunology*; D005260:Female; D005557:Formaldehyde / Q000494:pharmacology; D006183:H-2 Antigens / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011108:Polymers / Q000494:pharmacology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016707:Tissue Fixation
D000942:Antigens, Bacterial; D006183:H-2 Antigens; D011108:Polymers; D005557:Formaldehyde; C003043:paraform