Comparison between the Effect of Intranasal and Subcutaneous BCG Immunization on Nitric Oxide Production in Macrophages and Parasite Burden in Infected BALB/c Mice with Leishmania Major

In this research, the effect of intranasal and subcutaneous BCG vaccination was compared on nitric oxide production by peritoneal macrophages and the load of parasite burden in liver and spleen of infected BALB/c mice. Twenty male 6-8 weeks old BALB/c mice were vaccinated with appropriate dose of BCG through intranasal and subcutaneous routs. They received autoclaved Leishmania major plus alum (ALM+alum) subcutaneously one month later. After 21 days mice were challenged with the injection of 105 Leishmania major in the hind footpad and lesion development evaluated weekly. Efficacy of BCG vaccine determined by delayed type hypersensitivity assay. The amount of nitric oxide production in supernatant of macrophage culture was determined by Gries method and the load of parasite in liver and spleen was measured by parasite burden assay at different time periods. Stimulatory effect of BCG on immune system observed in both group vaccinated according to delayed type hypersensitivity response. Three weeks after challenge, nitric oxide production increased in both BCG vaccinated groups. But afterwards, BCG vaccinated groups had a considerable level of variations in nitric oxide production that finally tend to disease overcome in both BCG vaccinated groups. According to results of parasite burden, we found that in spite of the activation of both intranasal and subcutaneous routes of BCG vaccination against leishmaniasis, the infected host failed to overcome disease. In addition there was no significant difference between intranasal and subcutaneous routes of immune stimulation outcome (p≤0.05). There was no difference between intranasal and subcutaneous routes of BCG vaccination on nitric oxide production, parasite burden and host resistance. To have a good comparison for these two routes of vaccination, more studies about the kind and population of activated T cells is necessary. However, mucosal route of vaccination has a permanent advantage and can help to the prevention of dissemination of dangerous disease like HIV through infected needles. Mucosal vaccines can replace easily with common vaccination procedure, after efficacy improvement.