The debate over the effector function of eosinophils in helminth infection: new evidence from studies on the regulation of vaccine immunity by IL-12
Mem. Inst. Oswaldo Cruz
;
92(supl.2): 105-8, Dec. 1997.
Article
in English
| LILACS
| ID: lil-202020
RESUMO
The production of Th1-type cytokines is associated with strong cell-mediated immunity while Th2-type cytokines are typically involved in the generation of humoral immune responses. In mice vaccinated a single time (1x) with attenuated cercariae of Schistosoma mansoni, the immunity induced is highly dependent on CD4+ T cells and IFN-gamma. In contrast, mice vaccinated multiple times (3x) have decreased IFN-gamma expression, develop a more dominant Th2-type cytokine response as well as protective antibodies which can passively transfer immunity to naive recipients. Previously, we demonstrated the ability of IL-12, a potent IFN-gamma-inducing cytokine to enhance (1x) schistosome cell-mediated immunity when administered during the period of immunization. More recently, we asked what effects IL-12 would have on the development humoral-based immunity. While multiply-immunized/saline-treated mice demonstrated a 70-80 per cent reduction in parasite burden, 3x/IL-12-vaccinated animals displayed an even more striking >90 per cent reduction in challenge infection, which many mice in the later group demonstrating complete protection. Analysis of pulmonary cytokine mRNA responses demonstrated that control challenged mice elicited a dominant Th2-type response, 3x/saline-vaccinated produced a mixed Th1/Th2-type cytokine response, while 3x/saline-vaccinated produced a mixed Th1/Th2-type cytokine response, while 3x/IL-12 immunized animals displayed a dominant Th1-type response. The IL-12-treated group also showed a marked reduction in total serum IgE and tissue eosinophilia while SWAP-specific IgG2a and IgG2b Abs elevated. Interestingly, animals vaccinated with IL-12 also showed a highly significant increase in total Ig titers specific for IrV-5, a known protective antigen. More importantly, 3x/IL-12 serum alone, when transferred to naive mice reduced worm burdens by over 60 per cent while 3x/saline serum transferred significantly less protection. Nevertheless, animals vaccinated in the presence of IL-12 also develop macrophages with enhanced nitric oxide dependent killing activity against the parasites. Together, these observations suggest that IL-12, initially described as an adjuvant for cell-mediated immunity, may also be used as an adjuvant for promoting both humoral and cell-mediated protective responses.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Schistosoma mansoni
/
Vaccines
/
Interleukin-12
/
Eosinophils
/
Helminthiasis
Limits:
Animals
Language:
English
Journal:
Mem. Inst. Oswaldo Cruz
Journal subject:
Tropical Medicine
/
Parasitology
Year:
1997
Type:
Article
/
Congress and conference
Similar
MEDLINE
...
LILACS
LIS