The quantitative determination of the extent of despeciation of modified equine antitoxin.

This research paper presents a method to estimate the reactivity of antitoxins derived from horse plasma by observing the skin reactions of sensitized rabbits. It provides insights on factors affecting reactivity and establishes a correlation with anaphylactic tests in guinea pigs. Moreover, the reactivity found in human subjects also aligned with the results from the rabbit skin test.

Methodology

• The study presents a method to estimate how well antitoxins derived from horse plasma match with horse serum, by observing skin reactions in sensitized rabbits.
• This study showed it is possible to test four different preparations on three rabbits each, delivering reliable results within specific limits.

Observations on Dose and Reactivity

• The study found that as the sensitizing dose increased, the relative reactivity of a given test substance seemed to increase. However, this function levelled out at higher doses.
• The larger the sensitizing dose, the less variance there was in the relative reactivity within its replicates, implying a more reliable result with larger doses.

Insights on Desensitization and Sensitization

• Upon a second skin challenge, the control and test reaction diameters moved in opposite directions. This highlighted a simultaneous desensitization to normal horse serum and sensitization to the modified antigen.
• The time between sensitization and skin challenge (two, three, or four weeks) did not impact the values obtained for relative reactivity, suggesting that the response remains stable over time.

Correlations with Other Tests

• The relative skin reactivity of various substances, as determined in sensitized rabbits, correlated with anaphylactic tests in guinea pigs. This suggests a possible standardization of tests across different species.
• The less reactive of two materials in human subjects was also less reactive when tested using the rabbit skin test, strengthening the validity of the rabbit skin test as a predictive measure of reactivity in humans.