Human T cell proliferative responses to particulate microbial antigens are supported by populations enriched in dendritic cells.
The efficacy of dendritic cells in antigen presentation was studied in eight healthy subjects using a lymphoproliferation assay. Both particulate (Mycobacterium leprae, H37Ra) and soluble (PPD, tetanus toxoid) bacterial antigens were used as stimulants over a concentration range of accessory cells (monocytes (MO) and dendritic cells (DC)) varying from 10 to 0.1% in co-cultures using T-enriched cells. In general, co-cultures with T + MO and T + DC at all concentrations of accessory cells showed significant improvement of antigen-induced lymphoproliferation over PBMC cultures. The improvement in delta ct/min of T + DC co-cultures as compared to T + MO with parallel concentrations of accessory cells (P less than 0.05 to less than 0.01) was significant. Of the bacterial antigens used to test the antigen-presenting ability of DC, the particulate antigen (H37Ra) showed the most impressive improvement (380%) of T cell proliferation in DC reconstituted cultures as compared to monocytes. PPD, soluble protein derived from a similar tuberculosis strain of mycobacteria, was not presented as effectively as the particulate equivalent even though the donors of the appropriate cell combinations showed skin test reactivity to this antigen.
Mittal
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Department of Pathology, All India Institute of Medical Sciences, New Delhi.
Nath
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D000942:Antigens, Bacterial / Q000276:immunology*; D002455:Cell Division; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D009000:Monocytes / Q000276:immunology; D009161:Mycobacterium / Q000276:immunology; D009166:Mycobacterium leprae / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013745:Tetanus Toxoid / Q000276:immunology; D014373:Tuberculin / Q000276:immunology
D000942:Antigens, Bacterial; D013745:Tetanus Toxoid; D014373:Tuberculin