Identification of a 94‐kilodalton antigen on Leishmania promastigote forms and its specific recognition in human and canine visceral leishmaniasis

Abstract

We have analysed by immunoblotting sera from humans and dogs with visceral leishmaniasis, from the Old World as well as the New. When lysates of promastigotes are used as antigens, antibodies against a 94 kDa Leishmania component are detected, regardless of the age and geographical origin of the patient, the serum antibody titre as measured by indirect immunofluorescence, and the number of arcs in counterimmunoelectrophoresis. Low dilutions of sera from patients with Old and New World cutaneous leishmaniasis did not react with the 94-kDa antigen, whatever the species of Leishmania used as antigens. Sera from patients with other infections than leishmaniases, or without infection, are negative, even at low dilution. Anti-94 kDa antibodies were detected in the sera of Leishmania-infected dogs from both the Old and the New World. When lysates of Leishmania mexicana axenic amastigotes are used as antigens, the 94-kDa antigen was little or none identified by sera from humans and dogs with visceral leishmaniasis, and never recognized by control sera. Thus, the specific recognition of the 94-kDa promastigote antigen in human and canine visceral leishmaniasis suggests that this antigen could be a potential candidate in the differential immunodiagnosis of the disease.

Diagnostic potential of Western blot analysis of sera from dogs with leishmaniasis in endemic areas and significance of the pattern.

“…However, some investigators disagree as to the most specific and sensitive antigen bands recognized by sera of patients and animals with leishmaniasis. [6][7][8][9][10][11][12] Differences in the antigens used, promastigotes from the exponential or stationary growth phase, different degrees of antigen reduction as a consequence of different concentrations of SDS and 2-mercaptoethanol in the sample buffer, and separation of the soluble fractions of the antigen and the pellet are some of the factors that could influence the results. Moreover, the size of the slab gels and the concentration of polyacrylamide used, as well as different molecular weight markers, may introduce slight variations in the separation of the fractions and in the relative molecular weights calculated.…”

“…Recent studies [6][7][8] reported different results concerning the pattern obtained in Western blot analysis of the specific humoral immunoresponse to L. infantum antigens during the active course of the disease and during therapy in human leishmaniasis. Limited studies have been performed on dogs, 7,[9][10][11][12] and little is known about the natural evolution of this immunoresponse during active or latent asymptomatic canine infection, or during regression of the disease.…”

“…Limited studies have been performed on dogs, 7,[9][10][11][12] and little is known about the natural evolution of this immunoresponse during active or latent asymptomatic canine infection, or during regression of the disease.…”

The biological diagnosis of leishmaniasis in HIV-infected patients

“…Among and parasite. Sera reacting with leishmanial immunocompetent subjects in India, such antigens of 230, 75, 66, 50, 42, 18, 14 and rK39-based dipsticks, speci cally designed 12 kDa (Hoerauf et al, 1992), 65-66, 42, for rapid diagnosis under eld conditions, 14 and 12-13 kDa (Bogdan et al, 1990), have proved to be both highly sensitive and 94 kDa (Rolland et al, 1994) or 14, 18, 21, highly speci c in the serodiagnosis of VL 23 and 31 kDa (Marty et al, 1995) may (Sundar et al, 1998 and post-kala-azar only come from cases of leishmaniasis. In dermal leishmaniasis (Salotra et al, 2001).…”

Proteomic Approach for Characterization of Immunodominant Membrane-Associated 30- to 36-Kilodalton Fraction Antigens ofLeishmania infantumPromastigotes, Reacting with Sera from Mediterranean Visceral Leishmaniasis Patients

“…One drawback of serological assays with whole parasites is the existence of cross-reactivity with other pathogens, including Trypanosoma cruzi, mycobacteria, malaria parasites, or amoebae, which are coendemic with Leishmania in many parts of the world (7,51). The performance of serodiagnostic assays could be improved by using purified or recombinant leishmanial antigens, such as gp63 (40,41,56), Hsp70 (30,48), p94 (53), gp70 and p72 (24), p32 (61), rK39 (2,11), r gene B protein (rGBP) (15,31), H2A and H2B (31,57,58,59), rLACK (31), and the promastigote surface antigen 2 (rPSA-2) (18,31,37), or synthetic peptides (14,48) and antigens from promastigote-conditioned media (33).…”