In the more intensely studied human infections caused by Neisseria and Haemophilus species, the transferrin receptors have been shown to be present in some of the commensal species, and early studies in Neisseria (Harrison et al., 2008) indicated that although some clustering can be observed, it would be challenging to target the immune response exclusively on TbpBs in the pathogenic species. The gene discussed is TFRC; the disease is infection.