Early human infection with Onchocerca volvulus is associated with an enhanced parasite-specific cellular immune response.
The immune response after early exposure to or infection with Onchocerca volvulus was investigated in an autochthonous focus caused by the migration of infected persons to a previously unaffected area in Ecuador. Peripheral blood mononuclear cell (PBMC) proliferative and cytokine responses (interferon [IFN]-gamma and interleukin [IL]-5) to filarial antigens were measured in 14 subjects with serologic evidence of exposure and in 7 subjects with evidence of dermal microfilarial DNA and were compared with responses in 43 subjects with chronic O. volvulus infections. PBMC proliferative and cytokine responses (IFN-gamma and IL-5) to parasite antigens were elevated in the early exposure/infection group, compared with those in the chronic infection group. Addition of an IL-10-neutralizing antibody to filaria antigen-stimulated cultures resulted in significantly elevated proliferative responses in the chronic infection group. The findings suggest that early exposure and early parasite patency are associated with a vigorous cellular response, but, as infections become chronic, the cellular response becomes down-regulated, partly through an IL-10-dependent mechanism.
Cooper
P J
PJ
Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA. pc102d@hotmail.com
Mancero
T
T
Espinel
M
M
Sandoval
C
C
Lovato
R
R
Guderian
R H
RH
Nutman
T B
TB
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D002648:Child; D018509:DNA, Helminth / Q000032:analysis; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000032:analysis; D016753:Interleukin-10 / Q000276:immunology; D015848:Interleukin-5 / Q000032:analysis; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D017181:Onchocerca volvulus / Q000276:immunology / Q000302:isolation & purification; D009855:Onchocerciasis / Q000276:immunology / Q000469:parasitology*; D016133:Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000276:immunology
D000947:Antigens, Helminth; D018509:DNA, Helminth; D015848:Interleukin-5; D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D007371:Interferon-gamma