Human dendritic cells are superior to B cells at presenting a major histocompatibility complex class II-restricted heterologous antigen expressed on recombinant Streptococcus gordonii.
Bacteria are being actively investigated as vaccine carriers for inducing or boosting protective immune responses. In this study, human monocyte-derived dendritic cells (DCs) and normal B cells were compared for their capacity to present the C fragment of tetanus toxin (TTFC), expressed on the surface of recombinant Streptococcus gordonii, to specific CD4(+) T lymphocytes. DCs were more efficient than B cells at presenting soluble TTFC and remarkably more capable of presenting bacterium-associated TTFC both in terms of the amount of antigen required to obtain a given T-cell response and on a per-cell basis. This difference was associated with a much lower capacity of B cells to endocytose soluble TTFC and phagocytose recombinant S. gordonii. In addition, S. gordonii induced the phenotypic maturation of DCs but not of B cells. The results thus indicate that DCs but not B cells play a crucial role in the amplification of class II-restricted immune responses induced by immunization with recombinant gram-positive bacteria.
Corinti
S
S
Laboratory of Immunology, Istituto Dermopatico dell'Immacolata, IRCCS, Rome, Italy. imm1@idi.it
Medaglini
D
D
Prezzi
C
C
Cavani
A
A
Pozzi
G
G
Girolomoni
G
G
D017951:Antigen Presentation; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018925:Chemokines / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D004705:Endocytosis / Q000276:immunology; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D007963:Leukocytes, Mononuclear / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology; D011995:Recombination, Genetic; D013291:Streptococcus / Q000235:genetics / Q000276:immunology*; D013744:Tetanus Toxin / Q000276:immunology; D013997:Time Factors
D018925:Chemokines; D000949:Histocompatibility Antigens Class II; D013744:Tetanus Toxin