**8. The late phagosome**

Rab5 is lost as the phagosome matures and Rab7 appears on the membrane which mediates the fusion of the phagosome with late endosomes [38]. Similarly proteins that will be recycled are separated through sorting of vesicles whereas the proteins intended for degradation are eliminated in intraluminal vesicles and dare directed into the lumen of the phagosome [39], which will make it a little acidic due to the

**Figure 2.** *The phagolysosome.*

*Functioning and Control of Phagocytosis DOI: http://dx.doi.org/10.5772/intechopen.110511*

action of V-ATPase molecules on the membrane [40]. The lysosomal associated membrane proteins (LAMPS) and luminal proteases cathepsins and hydrolases) are incorporated from fusion with late endosomes or from the Golgi apparatus [41]. This well-illustrated in the **Figure 2**.

To mature to phagolysosomes these late phagosome fuse with lysosomes, which are the definitive microbicial organelles [42, 43]. Phagolysosomes have many sophisticated mechanisms that eliminate and degrade microorganism. They usually contain degradative enzymes like proteases, lysozymes, lipases and cathepsins, they are also acidic (ph. 5–5.5), due to the presence of V-ATPase molecules on their membrane [44]. This phagolysosome also presents with NADPH oxidase responsible for producing reactive oxygen species that are bactericidal like the superoxide (02-) [45] superoxide dismutase to H2O2 that can react Cl- ions to form hypochlorous acid, a very potential microbicial substance. This final reaction is catalyze by enzyme myeloperoxidase [46]. The best anti microbicial agent of neutrophils is hydrogen peroxide despite it being bactericidal, in its own way it can be anti-fungal and antiviral using myeloperoxidase in presence of hyalide ions [47].

### **9. Strategies pathogens use to evade phagocytosis**

The importance of phagocytosis cannot be under scored in the prevention and clearance of infection and its because of this that mic robes have devised different means to dodge recognition and eventually phagocytosis **Table 2.**

Mostly the microbes interfere with opsonins binding of polysaccharide-based capsules which shield the deposition of opsonins, while other bacteria express some surface proteins that inhibit binding for example Group A streptococci escape complement mediated phagocytosis using M proteins that are lacking in higher organisms [48]. These PAMPs are usually detected by receptors on the phagocyte particularly Toll like receptors. fc and complement receptors are the best studied receptors and there signaling is quite known more phagocytic receptors studies are ongoing.



*Abbreviations: CR, complement receptor, GAP, GTPase-activating proteins, GEF, guanine nucleotide exchange factor, HIV, human immunodeficiency virus, T4SS, type 4 secretion system.*

#### **Table 2.**

*Shows different virulent factors microbes use to dodge uptake by phagocytosis.*
