**2.2 "Zipper" phagocytosis**

In the initial stages of nonmyeloid cell phagocytosis, one of the primary processes is the "Zipper" mechanism [6, 80, 81]. The zipper mechanism was first coined in 1975 by Griffin *et. al* to describe the phenomena of attachment of opsonized erythrocytes and macrophages [82, 83]. Essentially, the structure is opsonized by immunoglobulins and becomes engulfed by a sequential recognition by Fcγ receptors in a "zipper" like fashion [80, 81]. Since this initial observation, similar phagocytic mechanisms have been noted that do not require opsonin-Fcγ receptor-mediated recognition, including mechanisms of phagocytosis by nonmyeloid cells. Instead, the pathogen engages with a component of the target cells' external structure. Such structures are typically cell surface integrins, adhesins, or invasins [4, 6, 34, 84]. This interaction initiates microtubule and actin rearrangements within the host cell. Following engagement, a continuous and sequential binding of the host cells "target structures" to the corresponding structures on the pathogen, leads to the complete engulfing and internalization of the pathogen by the cell in a phagosome-like vesicle, similar to that observed with opsonized mediated phagocytosis (**Figure 2**, [7, 81]).
