Immunoreactivity of proteins within 30-40 kDa range during the acute and the recovery phases in rats experimentally infected with Strongyloides venezuelensis

Abstract

In experimental infection with Strongyloides venezuelensis, the acute and recovery phases can be distinguished, unlike human infections caused by Strongyloides stercoralis. The objective of this study was to evaluate the production of anti-Strongyloides IgG antibodies and the recognition of immunogenic protein bands during the acute and the recovery phases in rats experimentally infected with S. venezuelensis. Rats were infected subcutaneously with 400 or 4,000 S. venezuelensis infective larvae. The acute phase was characterized by elimination of a large number of eggs in the faeces on days 6-14 post infection; the recovery phase was characterized by the resolution of the infection between days 30 and 35 post infection. Differences in IgG levels were observed in the acute and the recovery phases. Different antigenic fractions were recognized in both phases of infection. It is concluded that proteins within the 30-40 kDa range are immunoreactive markers for both the acute and the recovery phases in rats experimentally infected with S. venezuelensis, particularly using membrane antigen.

Figure 1. Eggs per gram of faeces (A) and IgG anti-S. venezuelensis in serum samples (B) from rats experimentally infected with 400iL3 and 4000iL3 S. venezuelensis. (A) Results are expressed as means ± SEM of five rats per group. (B) ELISA test using soluble (SAg) and membrane (MAg) antigens from S. venezuelensis filariform larvae on days 2, 7 and 35 post infection (pi). Data are expressed as means ± SEM (n = 5), **p = 0.0055, ## p = 0.0024. Dashed lines indicate the mean optical density of the negative control ± SEM (n = 5).

Figure 2. - Recognition of antigenic bands (soluble fraction [SAg, A] and membrane fraction [Mag, B]) in serum samples from rats experimentally infected with S. venezuelensis (400iL3 and 4000iL3) on days 2, 7 and 35 post infection (pi) (n=5).