The left lung is preferentially targeted during experimental paracoccidioidomycosis in C57BL/6 mice

Paracoccidioidomycosis (PCM) is a chronic systemic mycosis caused by theinhalation of the thermally dimorphic fungus Paracoccidioidesbrasiliensis as well as the recently described P.lutzii. Because the primary infection occurs in the lungs, weinvestigated the differential involvement of the right and left lungs inexperimental P. brasiliensis infection. Lungs were collectedfrom C57BL/6 mice at 70 days after intravenous infection with 1×10⁶yeast cells of a virulent strain of P. brasiliensis (Pb18). Theleft lung, which in mice is smaller and has fewer lobes than the right lung,yielded increased fungal recovery associated with a predominant interleukin-4response and diminished synthesis of interferon-γ and nitric oxide compared withthe right lung. Our data indicate differential involvement of the right and leftlungs during experimental PCM. This knowledge emphasizes the need for anaccurate, standardized protocol for tissue collection during studies ofexperimental P. brasiliensis infection, since experiments usingthe same lungs favor the collection of comparable data among different mice.