Proteins ofNippostrongylus brasiliensis analyzed by immunoblotting

Abstract

Antigenic proteins were characterized by the immunoblotting technique with sera from rats and mice after infection as well as hyperimmune sera. The immune response of infected animals was mainly directed toward five proteins of adult worms (190, 118, 110, 98, and 52 kDa) and four proteins of the third larval stage (L3; 92, 78, 58, and 24 kDa). The immunoblots indicated that stage-specific proteins of the homogenates were recognized. Three stage-specific proteins of L3 larvae (150, 135, and 125 kDa) and three proteins typical to the adult worm (100, 82, and 67 kDa) were identified. The majority of the worm proteins elicited an IgG response. IgE synthesis was induced by living and dead parasites and was directed towards four proteins (190, 150, 125, and 98 kDa). Three proteins additionally induced an IgG or IgM antibody response. The immune response as shown by the immunoblotting technique seems to be directed towards (1) antigens that are present for the duration of an infection and (2) stage-specific antigens that are expressed for only a short time during the life cycle of the parasite.

Modulation of B-Cell Proliferative Response by a Soluble Extract ofNippostrongylus brasiliensis

“…In addition, there is a paucity of evidence relating the exposure of hosts to somatic molecules from nematodes, and it is very reasonable to assume that somatic products from dead or dying worms can influence the host. Indeed, antibodies to somatic antigens are found in a variety of nematode infections, thus confirming exposure to somatic products in these infections (11,24,32,44).…”

“…It is possible that the stage-specific expression of the immunomodulatory factor could be an adaptation by the adult nematode to immunosuppress the host during the critical egg-producing stage. This shift in protein composition as nematodes develop from larvae to adults has been well documented, including in the nematode N. brasiliensis (11,24,32). Because the extract used in this study is a whole-worm homogenate, we do not know if the modulatory factor is secreted (thus raising the question of clinical relevance).…”

“…Because of the changes in protein composition associated with the developmental life cycle of nematodes (11,24), the effect of an extract from the infective larvae (thirdstage larvae) of N. brasiliensis was compared to the adult extract. B cells stimulated with LPS were cultured in the presence of extracts from either the infective larvae of N. brasiliensis (LWH) or the adult stage (AWH), and proliferation was assessed as described previously.…”

Effect of Antigens from <i>Nippostrongylus brasiliensis</i> and Cytokines on the Ongoing IgE Synthesis in vitro

“…Based on the results with individual antigen fractions bound to nitrocellulose it is shown that only a small num ber of antigens increased the IgE production. As wc dem onstrated in previous experiments IgE antibodies reacted only with proteins of the WH [12]. A comparison of the immunoblot analysis with the results obtained by the cell cul tures incubated with antigen fractions suggests that the IgE-binding and the IgE-cnhancing fractions belong to the same molecular weight ranges.…”

“…It was the purpose of our investigations to analyze the influ ence of soluble N.b. antigens previously characterized by immunoblotting [12] in the presence or absence of cyto kines in T/B cell cocultures as well as Transwell cultures.…”