IgY antibodies for the immunoprophylaxis and therapy of respiratory infections

Abbas, Aymn Talat; El-Kafrawy, Sherif Aly; Sohrab, Sayed Sartaj; Azhar, Esam Ibraheem Ahmed

Several studies have suggested that IgY can enhance phagocytic activity against invading pathogens. For example, IgY improved phagocytosis of Staphylococcus aureus by neutrophils 64 as well as the phagocytic activity against E. coli by milk macrophages and polymorphonuclear neutrophil leukocytes. 65 Studies have also shown that binding of specific IgY on the surface of Salmonella typhimurium 63 and E. coli O111 65 leads to structural alterations that can be detected using electron cloud and/or electric field on the bacterial surface. 63 Such changes can increase the susceptibility of bacterial cells to phagocytosis. A recent in vitro study showed that IgY opsonization of P. aeruginosa augments the PMNmediated respiratory burst and subsequent bacterial elimination.- 66 The researchers found that viable bacteria are reduced by 87% when anti-P. aeruginosa IgY is used to opsonize the bacteria prior to phagocytosis ( Figure 1A) . Adding IgYs to a bacterial suspension caused bacterial clumping and immobilization within minutes of opsonization, as shown by indirect immunofluorescence. The addition of IgY enlarged the target geometry through bacterial aggregation, which augmented phagocytic efficiency. 66 Neutralization IgY can prevent internalization of S. aureus by mammary epithelial cells, leading to neutralization of bacterial toxins. 67 On the other hand, IgYs can inhibit cell-to-cell spread of virus particles, thus suppressing viral colonization. 61 Figure 1 . Structural comparison between mammalian IgG and avian IgY.