Omega-3 polyunsaturated fatty acids (n
-3 PUFA) can modulate the immune system and their primary effect is on macrophage function. Paracoccidioidomycosis (PCM) is an endemic systemic mycosis in Latin America that is caused by the dimorphic fungus Paracoccidioides brasiliensis
(Pb). Macrophages are the main defence against this pathogen and have microbicidal activity that is dependent on interferon-γ and tumour necrosis factor (TNF)-α. These cytokines stimulate the synthesis of nitric oxide (NO) and hydrogen peroxide (H2
), leading to the death of the fungus. To study the effect of n
-3 PUFA on the host immune response during experimental PCM, macrophages that were obtained from animals infected with Pb18 and fed a diet enriched by linseed (LIN) oil were cultured and challenged with the fungus in vitro. The macrophage function was analysed based on the concentrations of TNF-α, NO and H2
. LIN oil seems to influence the production of TNF-α during the development of disease. A diet enriched with LIN oil influences the microbicidal activity of the macrophages by inducing the production of cytokines and metabolites such as NO and H2
, predominantly in the chronic phase of infection.