Immunological and allergenic responses induced by latex fractions of Calotropis procera (Ait.) R.Br.

Immunological and allergenic responses against the latex of Calotropis procera were investigated in mice by oral and subcutaneous routes. The latex was fractionated according to water solubility and molecular size of its components. The fractions were named as non-dialyzable latex (NDL) corresponding to the major latex proteins, dialyzable latex (DL) corresponding to low molecular size substances and rubber latex (RL) which was highly insoluble in water. Anti-sera against these fractions were assayed for total IgG and IgA titration by ELISA and IgE and IgG(1) were quantified by passive cutaneous anaphylaxis (PCA) in rats and mice, respectively. None of the fractions induced antibodies level increases when mice received latex fractions by oral route and thus, did not develop allergy. Nonetheless, anti-sera of mice sensitized with NDL and RL by subcutaneous route displayed considerable immunological response while DL did not. IgG level augmented consistently against NDL and RL while IgA response was detected only to NDL. NDL and RL induced very strong PCA reactions suggesting that both fractions would contain latex substances involved in allergy. Furthermore, protein analysis of NDL and RL suggests that RL still retain residual proteins abundantly found in NDL that could explain its similar allergenic effect. No IgG(1) reaction was detected in any of the anti-sera tested. According to the results, the proteins of latex of Calotropis procera can provoke allergy by subcutaneous route. The NDL has previously shown to display anti-inflammatory and analgesic activities by intraperitoneal injection. It should be relevant to determine whether NDL could induce such activities when assayed by oral route since it was ineffective to induce allergy by this way.

Pro- and anti-inflammatory activities of the latex from Calotropis procera (Ait.) R.Br. are triggered by compounds fractionated by dialysis.

OBJECTIVES AND DESIGN: Previous studies have described pro- and anti-inflammatory activities displayed by the latex from Calotropis procera. This report aims to clarify these observations and shows that such activities can be segregated from the whole latex. METHODS: The latex was divided into water-soluble fractions devoid of poly-isoprene by centrifugation and dialysis and both the activities were assayed by the peritonitis model in rats. The drugs dexamethasone, thalidomide, meclizine, indomethacin and celecoxib were used to modulate the inflammatory stimuli. RESULTS: Inflammation in rats was observed 2 h after intraperitoneal administration of the stimulus (DL fraction) in a dose dependent manner. This activity was inhibited by previous intravenous injection of dexamethasone, thalidomide and meclizine. Indomethacin and celecoxib did not reverse inflammation. These results suggest the involvement of histamine release and TNF-alpha mediated inflammation while prostaglandins seem not to be required. The anti-inflammatory fraction (NDL) inhibited inflammation triggered by proinflammatory fraction (DL) suggesting that NDL ought to follow a similar pathway of action to that of the anti-inflammatory drugs that were able to inhibit inflammation triggered by DL. CONCLUSIONS: Pro- and anti-inflammatory activities of the latex are displayed by compounds suitable to be fractionated on the basis of their molecular size.