Question

1. Which of the following pairs of statements are true regarding the immune system

1. Primary organs of the immune system are generative. The thymus gives rise to both B and T cells
2. Primary organs of the immune system are generative. Maturation of both B and T cells occur in the bone marrow.
3. B cells originate in the bone marrow. T cells originate in the thymus
4. Maturation occurs in the secondary lymph organs. T and B cells mature in the spleen or lymph node depending on where they are needed
5. Primary organs of the immune system are generative. Antigen-lymphocyte interactions occur in the spleen for systemic pathogens

1. Which of the following represent general function(s) associated with EVERY cytokines

1. All of the answers are correct
2. Direct chemotaxis
3. Hormone like factors that coordinate immune system efforts
4. Promote differentiation of hematopoietic stem cells
5. Small proteins that function in cell signaling

1. The toxic lipopolysaccharides produced by most Gram-negative bacteria is classify as what type of toxin

1. A/B toxin
2. Exotoxin
3. Cytolytic toxin
4. Enterotoxin
5. Endotoxin

Answer 1

1.C .B cells originate in the bone marrow. T cells originate in the thymus

E.Primary organs of the immune system are generative. Antigen-lymphocyte interactions occur in the spleen for systemic pathogens

B and T lymphocytes are produced by the multipotent hematopoietic stem cells present in bone marrow. B cells are maturing in bone marrow cells where as T cells are matured in the thymus. The B cells moves from the bone marrow after maturation and enters into the spleen for secondary maturation and become naive mature B cells.The spleen fucntions in clearing the pathogens and antigens develops in systemic circulation.

2.All of the answers are correct

The cytokines are secreted by the immune cells and that can be in the form of protein,peptides or glycoproteins. It attaract the pathogen by its chemical secretion and causes inflammation in immune response to kill the infected cells. It targets the hematopoietic progenitor cells and causes differentiation and survival of lymphoid and myeloid compartments.

3.e.Endotoxin

The outer membrane of gram negative bacteria is lipopolysachharides produces endotoxins.The lipopolysachharides consists of polysaccharids and lipid A responsible for the endotoxin activity. The A/B toxins are exotoxins produced by gram negative bacteria. The gram negative bacteria produces the cytolytic toxin in the form of virulens factor.Enterotoxins are plasma encoded exotoxins produced and secreted by bacterial and represents the pore forming toxins.