Question

1. T_H cells can recognize and respond to antigens from both extracellular and intracellular pathogens

1. True
2. False

1. Complement activation is directed against microbial pathogens. Which of the following describe the specific functions of the MBL protein in complement activation

1. Punctures cell walls and plasma membranes causing osmotic lysis
2. Induces vasodilation and increases vascular permeability
3. Promotes diapedesis of white blood cells
4. Decreases ribosome function during viral infection
5. Recognition of a microbial PAMP

1. Phagocytosis leads to the destruction of pathogens at the site of infection which of the following does not participate in the clearance of the pathogen by phagocytosis

1. Formation of the phagolysosome
2. Recognition of C3b molecules
3. All of the answers participate
4. Membrane attack complex (MAC) formation
5. Neutrophils
6. Binding to the Fc region of antibodies
7. Recognition of pattern associated molecular patterns

Answer 1

1. The correct option is Option b. False

Because TH cells can respond to antigens presented by class II MHC molecules which are exogenous antigens originating extracellularly from foreign bodies like pathogenic bacteria.

2. The correct option is Option e. Recognition of a microbial PAMP

This is the third pathway of complement activation that involves the specific pattern recognition of biomolecules present on pathogens called PAMP (pathogen associated molecular patterns). In this method, simple carbohydrates such as mannose and N-acetylglucosamine present on prokaryotes act as PAMPS which are identified by the binding of pattern recognition molecules including mannan-binding lectin (MBL) or ficolins to a bacterial membrane that expresses these simpler glycoproteins.

3. The correct option is Option c. All of the answers participate

All the events mentioned in the options participate in the pathogen clearance by phagocytosis. So we can not exclude any option.