Nitric oxide modulation of the immune response against cholera toxin-adjuvated ovalbumin administered by the intranasal route

Here, we studied the effect of aminoguanidine (AG) treatment, a nitric oxide synthase (NOS)-2 inhibitor, during the immune response against intranasal administration of ovalbumin (OVA) mixed with cholera toxin (CT) in BALB/c mice. NOS-2 mRNA was detected by reverse transcription-PCR (RT-PCR) in samples of lungs and turbinates early post-inoculation of the antigen. Animals intranasally treated with AG, showed an increase in the levels of seric specific IgG and IgM. A higher lgG1/IgG2a ratio against OVA was also observed in sera of same animals. Moreover, high levels of specific IgA were detected in samples of pulmonar washings obtained from treated animals. On the contrary, treated animals showed a lower DTH response while splenocytes obtained from the same animals showed a reduced proliferative capability against OVA compared to controls. Finally, RT-PCR analysis showed increased expression of TGF-beta in turbinates, lungs and cells from pulmonar washings obtained from AG treated mice. Taken together, these data suggest a role of nitric oxide (NO) in modulating the primary immune response against intranasal antigens. (C) 2004 Published by Elsevier B.V.