Immune response in dogs experimentally infected withParacoccidioides brasiliensis

Abstract

The aim of the present study was to evaluate the immune response of young dogs experimentally infected with Paracoccidioides brasiliensis. Six dogs were infected intravenously with P. brasiliensis and one control dog was inoculated with sterile saline. The infected animals were sacrificed in groups of two at 1, 6 and 12 months after infection. During the experimental period, the immune responses of the dogs to the fungus were followed by ELISA (IgM and IgG), by the immunodiffusion test and by the skin test with gp43. After killing the dogs, samples from several organs were submitted to histopathological analysis (H&E and Grocott stains) but the fungus was not observed in any tissue. Attempts to isolate the fungus from these tissue samples were also unsuccessful. All infected dogs, except one, reacted positively to the immunodiffusion and skin tests. All infected dogs showed a humoral immune response to the gp43 antigen detected by ELISA. The IgM and IgG response peaked by the first and second month, respectively. We conclude that young dogs appear to be resistant to the development of paracoccidioidomycosis.

Pulmonary immune responses induced in BALB/c mice by Paracoccidioides brasiliensis conidia

“…More than 20-years ago, animal models were used to measure the immune responses in PCM, initially in hamsters [4,5], mice [6][7][8][9], and then in guinea pigs [10,11] and bats [12]. Additionally, a recent study has utilized dogs to explore certain immune functions [13].…”

Activation of the alternative complement pathway in canine normal serum by Paracoccidioides brasiliensis

“…Our group has observed, in studies on experimental paracoccidioidomycosis in dogs aged three months (19) and adult (9), that probably puppies are susceptible and adults are resistant to disease development. The results of this study are in agreement with these data, taking into account that the activation of the alternative complement pathway by P. brasiliensis was higher in adult dogs than those under one year old.…”

“…The serum samples were stored at -80ºC until use. All the samples were negative to IgM and IgG against P. brasiliensis gp43 by the ELISA test, performed as previously described (9). …”

Paracoccidioides brasiliensis infection in dogs from Western Brazilian Amazon

“…In another study carried out by our group to evaluate infection by P. brasiliensis in urban dogs from Mato Grosso do Sul, a signiϐicantly lower positivity was observed in dogs under one year old (Silveira et al 2006). In studies on experimental paracoccidioidomycosis in dogs, puppies were more susceptible to developing paracocccidioidomycosis than adults (Ono et al 2003, Eisele et al 2004. This is the ϐirst study of P. brasiliensis infection in dogs from the Western Brazilian Amazon.…”