Donald S. Cox

Oral induction of the secretory antibody response by soluble and particulate antigens

The ability of gastric intubation of a soluble or a particulate form of dinitrophenylated bovine gamma-globulin (DNP-BGG) to induce salivary IgA antibody was examined. Gastric intubation of the particulate form of the antigen tended to induce a greater response than did equivalent doses of the soluble form. However, systemic immunization with the soluble form of the antigen prior to gastric intubation of antigen increased the salivary IgA response. Prior systemic injection of the particulate form did not increase the salivary IgA response. Immunoreactivity of the particulate moiety of the particulate antigen did not seem to be a factor in the observed differences, since three different synthetic particulate antigens with identical hapten-protein moieties produced the same results (i.e. prior injection with the synthetic particulate antigens did not increase the salivary IgA response).

IgA antibody produced by local presentation of antigen in orally primed rats

The effect of the introduction of antigen by gastric intubation on the locally stimulated mammary gland IgA antibody (Ab) response was examined. Rats receiving a particulate DNP antigen by gastric intubation prior to injection in the vicinity of the mammary glands ( MGV ) demonstrated increased levels of IgA Ab in milk. Soluble DNP antigen introduction by gastric intubation did not lead to increased IgA Ab levels in milk. Prior administration of either form of DNP antigen by gastric intubation did not affect the IgG response. Only those rats receiving particulate DNP antigen by intubation demonstrated salivary IgA Ab. Particulate forms of antigen administered by intubation can provide a means of increasing the locally induced IgA response at a secretory site.

An alternative statistical treatment for summarizing the central tendency of replicate assay data

Standard assay procedures call for multiple replicates for the purpose of averaging random error from individual replicate scores to obtain a reliable estimate of the true score and for the purpose of specifying the degree of variability within the assay. In this paper we focus on the variability and magnitude of within-assay replicates in order to improve the estimate of the true score. A rule is presented for deciding (1) when individual replicates should be omitted from the computation of the assays summary score or (2) when an entire sample of replicates should be discarded based on the pattern of replicate scores. It is suggested that this rule improves the reliability of the estimated assay score and this is supported by an illustrative analysis of lymphocyte proliferation assays.

A sensitive double isotope modification of the Farr assay using beta-particle emitters.

A sensitive modification of the ammonium sulfate precipitation assay for antibody affinity is described. The assay combines small reaction volumes and a 32P volume marker to determine the average relative affinity of small amounts of antibody to DNP hapten. The assay is relatively safe since two beta-particle emitters are utilized instead of two gamma-ray emitters. The assay has proven useful for the determination of small amounts of antibody such as might be found in secretions and column fractions.