In order to assess the role of luminal and intracellular IgG transport during acute bacterial infection requiring efficient recruitment of innate leukocytes, we first vaccinated WT and FcRn-deficient (fcgrt−/−) mice intranasally with formalin-killed P. aeruginosa to generate a pool of specific IgG in the lung as previously described (21). The gene discussed is FCGRT; the disease is bacterial infectious disease.