Effector function can also be operative at the cellular level. As an example, intestinal double-positive CD4(+)CD8(+) T cells kindle highly activated memory cells with an increased capacity to produce cytokines of which IL-17 is currently on the forefront.
Tetanus toxin-derived B cell epitopes can mediate the formation of immune complexes in the presence of circulating antibodies: the so formed complexes have been seen to improve CD8+T cell recall responses
Phages (viruses that infect bacteria) display proteins on their outside for which one has inserted an intended genetic information. Big data libraries of proteins lets us to select the one which we need for therapeutical purpose then to be amplified in bioreactors. Besides using the phage display technique for therapeutics, the study of protein-protein interactions becomes possible for diagnostic purposes in detail and one can produce affinity reagents. Functional specific protein-based inhibitors, called Affimer proteins, can be used to prevent immune complex binding to Fc gamma receptors hence blocking IgG interaction with single receptor specificities.
Under the electron microscope, factor H, now in the limelight of the drug-developing industry (www.optherion.com, www.taligentherapeutics.com), looks like beads on a string with the ability to fold back on itself.