Dados do Trabalho

Título

Sporothrix brasiliensis, Sporothrix schenckii and Felis catus: an in vitro interaction between the three zoonotic relevant species

Introdução

Since the mid-1990s Rio de Janeiro state, Brazil, has been increasingly affected by zoonotic sporotrichosis, currently a national hyperendemic and public health concern. In this scenario, two pathogenic species stood out: Sporothrix schenckii and Sporothrix brasiliensis ( > 95% of all zoonotic cases). The domestic feline presents the most severe clinical presentation of this mycosis and high fungal loads in its lesions, even when immunocompetent. Based on the “damage-response framework for fungal diseases” not only the microorganism’s virulence factors define the host signs and symptoms. The cat´s host response may play a central role in this species susceptibility to sporotrichosis.

Objetivo (s)

This work aimed at investigating the unprecedented in vitro interaction between cat phagocytes and the two major pathogens of zoonotic sporotrichosis.

Material e Métodos

This study was approved by the Ethics Committee for the Use of Animals (CEUA) of the Fluminense Federal University under protocol number 7561040518 on June 14th, 2018. Peripheral blood mononuclear cells-derived phagocytes (PBMCs) of healthy cats were cultivated and separately exposed to standard inoculum of S. schenckii (ATCC MYA 4820) or S. brasiliensis (ATCC MYA 4823) yeasts.

Resultados e Conclusão

Similarly, to what was observed for human macrophages both Sporothrix species were able to survive and form filaments inside feline host cells. High fungal loads reduced phagocytosis (p<0.0001) while the uptake of both agents by feline phagocytes is reduced in the presence of inactivated serum (p<0.0001). S. brasiliensis promoted a stronger cytotoxic effect on feline phagocytes (p<0.0226) while S. schenckii is less phagocytosed, producing filaments earlier than S. brasiliensis (p<0.0001). Sporothrix spp. yeast cells capacity to differentiate to hyphae inside feline phagocytes suggests a complex mechanism that may play a role in host cell damage. Our results add insights and open doors for more complex studies such as those involving cell receptors and fungal ligands recognition. Knowledge on the Felis catus immune response constitutes the first key step for a successful strategic program to prevent the animal disease and/or to a vaccine development and, ultimately, to mitigate the burden of the Brazilian sporotrichosis hyperendemics. 

Palavras Chave

Cat; Citotoxicity; Host-pathogen interaction; sporotrichosis; Zoonosis