1. Pattern recognition receptors bind to?

2. In an individual with an immediate hypersensitivity response (allergy) to dust mites, cross-linking of which of the following dust-mite-specific molecules will trigger inflammatory mediator release?

3. T-cell receptors, when coexpressed with CD8 mole­cules, are restricted to recognizing and binding peptide fragments associated with

4.A 2-year-old child exposed to an antigen for the first time already possesses a B cell with immunoglobulin specific for that antigen. This finding is best explained by