BCG-infected adherent mononuclear cells release cytokines that regulate group 1 CD1 molecule expression.
Increasing evidence is now available showing that CD1-restricted T cell responses against non-peptide mycobacterial antigens could play a role in the immune resistance against tuberculosis. BCG, widely used in anti-tubercular vaccination, shares various constituents with Mycobacterium tuberculosis, but does not provide full protection. In the present study we have investigated the pattern of group 1 CD1 molecule expression in adherent mononuclear cells (AMNC) of human peripheral blood, infected in vitro with BCG. Shortly after exposure to BCG, both BCG-positive and BCG-negative AMNC showed a moderate CD1 expression elicited by BCG-induced release of GM-CSF presumably acting through an autocrine and a paracrine mechanism. This was demonstrated using two-color flow cytometry with green fluorescent BCG and anti-CD1 PE-labeled antibodies. However, high CD1 expression induced by exogenously added GM-CSF in AMNC was reduced if target cells were cocultivated with BCG. Monoclonal antibodies against IL-10 partially restored CD1 expression, thus showing that IL-10, released from infected AMNC, is involved, at least in part, in CD1 negative modulation. Therefore, through a complex cytokine network, including not yet identified factor(s), BCG triggers but does not allow full expression of CD1 on AMNC. It cannot be excluded that this mechanism could play a role in the limited efficiency of BCG vaccination.
Prete
Salvatore Pasquale
SP
Department of Neuroscience, School of Medicine, University of Rome "Tor Vergata", Rome, Italy.
Giuliani
Anna
A
D'Atri
Stefania
S
Graziani
Grazia
G
Balduzzi
Alessandra
A
Oggioni
Marco Rinaldo
MR
Iona
Elisabetta
E
Girolomoni
Giampiero
G
Bonmassar
Laura
L
Romani
Luigina
L
Franzese
Ornella
O
D018949:Antigens, CD1 / Q000096:biosynthesis*; D002470:Cell Survival; D002478:Cells, Cultured; D018920:Coculture Techniques; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000502:physiology*; D006801:Humans; D016753:Interleukin-10 / Q000502:physiology*; D007963:Leukocytes, Mononuclear / Q000276:immunology* / Q000382:microbiology; D009163:Mycobacterium bovis / Q000276:immunology*
D018949:Antigens, CD1; D016753:Interleukin-10; D016178:Granulocyte-Macrophage Colony-Stimulating Factor