Specific IgG and immune complex responses to parthenogenetic females and eggs of nematodeStrongyloides venezuelensisfor the diagnosis of immunosuppression in infected rats

Abstract

In the present study, antigens from parthenogenetic females and eggs of Strongyloides venezuelensis, or anti-parthenogenetic-female and anti-egg antigens were used to detect specific IgG and immune complex responses, respectively. Serum samples from experimentally infected immunocompetent and immunosuppressed rats were analysed on days 5, 8, 13 and 21 post-infection (dpi). An enzyme-linked immunosorbent assay (ELISA) was performed using alkaline parasite extract for specific IgG detection, and anti-parthenogenetic-female or anti-egg antigens for immune complex detection. The data were analysed using analysis of variance (ANOVA), followed by a Bonferroni test. When parthenogenetic female or egg extracts were used as antigens, specific IgGs were not detected in either immunocompetent or immunosuppressed rats. When anti-parthenogenetic-female or anti-S. venezuelensis-eggs were used, immune complexes were detected for the duration of the infection in immunosuppressed animals and were only detected between 5 and 13 dpi in immunocompetent animals. The duration of infection was not significantly different between the immunocompetent and immunosuppressed groups when anti-parthenogenetic-female or anti-S. venezuelensis-eggs were used. Parthenogenetic female extracts yielded significant differences between antibody and immune complex responses in immunocompetent rats from 5 to 13 dpi, but only on day 5 dpi in immunosuppressed rats. Exposure to S. venezuelensis egg extract yielded significant differences in both antibody and immune complex detection between immunocompetent and immunosuppressed rats for the duration of the infection. In conclusion, ELISA using alternative antigens may be a successful strategy for identifying immune complexes in serum samples and diagnosing active strongyloidiasis, particularly under conditions of immunosuppression.

Prevalence of Strongyloides stercoralis infection and hyperinfection syndrome among renal allograft recipients in Central Europe

“…Type A causes infections in humans and dogs, while type B infects only dogs 4 . Chronically infected humans frequently do not show symptoms but can develop a disseminated disease following immunosuppressive or chemotherapeutic treatment 5 , 6 . The frequently asymptomatic or nonspecific nature of active S trongyloides infection leads to underdiagnosis and places immunosuppressed patients at increased risk of developing hyperinfection and adverse outcome 7 .…”

Strongyloidiasis Current Status with Emphasis in Diagnosis and Drug Research

“…Several studies have been published using murine models focusing in immunodiagnostic or in the host immune response, in an attempt to understand immunological aspects that are still unknown [ 4 – 10 ]. Immunosuppression has been correlated with the infection aggravation, mainly in cases of HTLV-1 virus coinfection, alcoholism, and corticoids use [ 11 – 14 ].…”

Strongyloides‐specific IgA, IgG and IgG immune complex profile in patients with pulmonary tuberculosis

“…Immune complexes perform an important role in the neutralization of infectious agents and are quickly eliminated from the blood flow through the innate immunological system. In addition, these immune complexes have been reported more frequently for parasitic diseases 11,27‐29 . The IgG‐IC high OD, in the groups, may be explained by the persistence of IgG antibodies in an undiagnosed infection due to the low release of larvae in the faeces and/or individuals with previous exposure residing in areas with a high prevalence of strongyloidiasis 11,30 .…”

“…The IgG‐IC high OD, in the groups, may be explained by the persistence of IgG antibodies in an undiagnosed infection due to the low release of larvae in the faeces and/or individuals with previous exposure residing in areas with a high prevalence of strongyloidiasis 11,30 . Immunological complexes participate in the physiopathology of the disease and, therefore, may reflect the immune response of each individual, enabling the control of this infection 28 …”