In the present study, the immunomodulatory effect of Neem (Azadirachtaindica)
seed aqueous, ethanolic extracts and Candida albicans cell wall mannoproteins on the
immune response of mice vaccinated with Brucella Rev-1 vaccine was investigated. The
study was conducted on two main groups(160 mice for each group), Each group was
divided into eight subgroups 20 mice for each (I: treated with distilled water, II: treated
with the Brucella Rev-1 vaccine, III: treated with mannoproteins, IV: treated with neem
aqueous extract, V: treated with neemethanolic extract, VI, VII and VIII: treated with
mannoproteins, neem aqueous extract and neemethanolic extract, respectively, then they
were vaccinated with Brucella Rev-1). All these treatments were carried out on day 1
and then vaccinated with brucella Rev-1 vaccine on day 4 .Then the mice were tested as
follows , on day 8 after vaccination(serum IFN-γ level), day 21 for (anti-Brucella
antibody titer). The doses of both plant extracts and mannoproteins represented 10% of
the calculated LD50 (neem extracts: 3.8096 g/Kg mannoproteins: 5.7144 mg/Kg), which
were given subcutaneously. Mice of the second main group were injected with the
immune suppressive drug prednisolone (5mg/Kg) 5 days prior to the treatments, which
carried out on mice of the first main group. The results demonstrated clear
immunomodulatory effects (improvement of non-specific, humoral immunity) of the
tested immunomodulators in mice vaccinated with Brucella Rev-1 as compared with
mice that were not treated with Neem extracts or mannoproteins. In this regard, The
interferon-γ showed a significant increase (P≤ 0.01) serum level in immunomodulatortreated
and -vaccinated mice in comparison with negative and positive groups, and again
group VII showed the highest increase. The anti-Brucella antibodies assessed by indirect
Immunoflourescent test also showed a significant increase titer in immunomodulatortreated
and -vaccinated mice in comparison with negative and positive groups .
Conclusion: The aqueous and ethanolicNeem seed extract reported the highest
enhancement in all immunological parameters employed in comparison with
mannoproteins of Candida albicans cell wall.