Recombinant Cysteine Proteinase B from Leishmania braziliensis and Its Domains: Promising Antigens for Serodiagnosis of Cutaneous and Visceral Leishmaniasis in Dogs

Abstract

Leishmaniasis represents a group of parasitic diseases caused by a protozoan of the genus Leishmania and is widely distributed in tropical and subtropical regions. Leishmaniasis is one of the major tropical neglected diseases, with 1.5 to 2 million new cases occurring annually. Diagnosis remains a challenge despite advances in parasitological, serological, and molecular methods. Dogs are an important host for the parasite and develop both visceral and cutaneous lesions. Our goal was to contribute to the diagnosis of canine cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) using the recombinant cysteine proteinase B (F-CPB) from Leishmania braziliensis and its N- and C-terminal domains (N-CPB and C-CPB) as antigens in an enzyme-linked immunosorbent assay (ELISA). Sera from dogs from Northwest Argentina diagnosed with CL were tested by ELISA against a supernatant of L. braziliensis lysate, the F-CPB protein, and its domains. We found values of sensitivity (Se) of 90.7%, 94.4%, and 94.3% and specificity (Sp) of 95.5%, 90.9%, and 91.3% for F-CPB and its N- and C-terminal domains, respectively. In sera from dogs diagnosed with VL from Northeast Argentina, we found Se of 93.3%, 73.3%, and 66.7% and Sp of 92.3%, 76.9%, and 88.5% for F-CPB and its N- and C-terminal domains, respectively. These results support CPB as a relevant antigen for canine leishmaniasis diagnosis in its different clinical presentations. More interestingly, the amino acid sequence of CPB showed high percentages of identity in several Leishmania species, suggesting that the CPB from L. braziliensis qualifies as a good antigen for the diagnosis of leishmaniasis caused by different species.

Reactivity of sera from dogs living in a leishmaniasis-endemic area to the COOH-terminal region of cysteine proteinase B

“…The possibility of rcyspep use as a tool in serological monitoring for canine leishmaniasis is reinforced by recent evidence on a recombinant CPB from L. (V.) braziliensis , and its domains, as serodiagnosis tool of dogs from endemic areas of cutaneous and visceral leishmaniasis in Argentina. 8 Further studies still need to be conducted to investigate the potential usefulness of cyspep as a tool in serological monitoring for canine leishmaniasis as well as in discrimination between symptomatic and oligosymptomatic dogs.…”

“…In this context, some studies have addressed the cysteine proteinase in humoral and cellular immune responses in canine VL and CL. 8 , 9 , 10 , 11 , 12 …”

Immunogenicity and potential protection of DNA vaccine of Leishmania martiniquensis against Leishmania infection in mice

“…CPB plays a role in reducing the function of Th1 cytokines, which have been associated with leishmaniasis pathogenesis [16]. In addition, Leishmania CPB has shown evidence as a suitable VL vaccine candidate antigen in mouse and canine infection models [17,18].…”