T cell epitope content is one of the factors that contributes to antigenicity. Glycosylation of HA does not correlate with either the antigenicity or the selection pressure. The serum is incubated with foreign red blood cells of known antigenicity. "P. gingivalis" is divided into K-serotypes based upon capsular antigenicity of the various types. Capsid proteins define cellular receptor specificity and virus antigenicity. Variant 2c however has a unique pattern of antigenicity. Although most of these mutants did not result in loss of antigenicity of TSST-1. The purported mechanism of action is cleavage of peptides masking the epitope, restoring antigenicity. The distinctions between the serotypes are based on their antigenicity. Literature review and BLOSUM scores were used to define potentially altered antigenicity.