Antibodies and immune effectors: shaping Gram-negative bacterial phenotypes

Antibodies and immune effectors (IE) are crucial for protecting humans from Gram-negative bacteria. Antibodies can bind outer membrane or cell surface (e.g. flagella) structures, thereby preventing adhesion, disrupting specific virulence functions, or targeting bacteria for phagocytosis. IE (antimicrobial peptides, cytokines and hormones) impinge on bacterial infections and regulate immune responses. A developing paradigm is that bacteria ‘recognize’ antibodies and IE, which alert them to challenging environments, promoting resistance phenotypes and increased virulence. A broader understanding of the interactions between bacteria and antibodies and IE will help define their relative contributions to pathogenesis, and perhaps indicate how we could use antibodies and IE to shape bacterial phenotypes that are easier for the immune system to control.