They are also involved in the production of cross-reactive antibodies.

As a result, age-specific antibody concentration data for any given serotype are "contaminated," to a greater or lesser degree, by cross-reactive antibodies with other specificties.

It is thought to occur when weakly cross-reactive antibodies form bridging complexes to facilitate uptake and replication of related but non-identical variants.

Interestingly, the introduction of T cell epitopes from a hen-egg lysozyme or ovalbumin into mouse TNF-alpha also resulted in an increased cross-reactive antibody response in mice [ 38 ] .

In cases of progressive multifocal leucoencephalopathy (PML), a cross-reactive antibody to SV40 T antigen (commonly Pab419) is used to stain tissues directly for the presence of JC virus T antigen.

Analyses by Soininen and colleagues have found that antibodies measured by standard ELISA in unimmunized children are highly cross-reactive between different serotypes, and that cross-reactive antibodies lack opsonophagocytic function and often appear in the absence of any documented exposure to a given capsular serotype.