Final answer:
The antibodies in antisera are often linked to latex beads to improve the visibility of agglutination, facilitating the detection of specific antigens or antibodies in patient serum.
Step-by-step explanation:
When using antisera to characterize bacteria, we will often link the antibodies to latex beads to better visualize the agglutination. This method, known as an indirect agglutination assay (or latex fixation assay), enhances the visibility of the agglutination which occurs when antibodies attach to the antigens present on the latex beads. Antisera against certain proteins allow for the identification of serovars within species of bacteria. Particularly, this technique is useful for detecting the presence of specific antigens or antibodies in patient serum, including IgM antibodies, which provide maximum cross-linking and are an indicator of diseases like rheumatoid arthritis.