📌 POINTS TO PONDER
🔹Pan-receptor defect: It is the defect in which all chemotaxin receptors are decreased. It is seen in localized aggressive periodontitis which is characterized by a decrease in chemotactic responses to a variety of chemotactic factors, including C5a, FMLP (formyl peptide) and leukotriene B4.
🔹CD, i.e, cluster of differentiation system are the group of receptors which enable the cell to interact with each other molecules/cells.
📣 Inflammatory actions of various chemical mediators :
⭐ Chemical Mediators Actions
🔺 PGI2 Vasodilatation
, PGE1
, PGE2
, PGD2
Bradykinin
🔺 Thromboxane A2, Vasoconstriction
leukotrienes C4
, D4
, E4
🔺 Leukotrienes, histamine, Increased
SRS-A, bradykinin permeability
🔺 Leukotriene B4, HETE, lipoxin Chemotaxis
🔺 Bradykinin Leukocyte adhesion
🔺 α2-macroglobin Collagenase activity
✳️Abbreviations:
(PGI2- prostacyclin; PGE2- prostaglandin E2; PGD2- prostaglandin D2; SRS-A, slow-reacting substance of anaphylaxis; HETE – hydroxyeicosatetraenoic acid)
📌 VIVA VOCE
Q1. What is the basic difference between microphages and macrophages?
Ans. Microphages are neutrophils which differentiate almost completely within bone marrow in 14 days and retain their small size of 10 μm when they exit from bone marrow whereas macrophages are modified monocytes, which exits from bone marrow after 2 days and increase in size to about 22 μm.
Q2. What is pan-receptor defect?
Ans. When all chemotaxin receptors are decreased, the defect is called pan-receptor defect. It is seen in localized aggressive periodontitis. It is characterized by a decrease in chemotactic responses to a variety of chemotactic factors, including C5a, FMLP (formyl peptide) and leukotriene B4.
Q3. What is Neutrophil extracellular trap (NET)?
Ans. These are network of extracellular fibers primarily composed of DNA from neutrophil, chromatin and nucleosomes. Neutrophils can kill pathogens extra-cellularly by releasing neutrophil extracellular traps. It is considered as last resort by neutrophils to kill.
Q4. What is ADCC?
Ans. Antibody‐dependent cell‐mediated cytotoxicity is the non-phagocytic killing of an antibody‐ coated target cell by a cytotoxic effector cell. It is a process of cell-mediated immune defense and usually associated with the release of the content of cytotoxic granules or by the expression of cell death‐inducing molecules.
Q5. What are the types of T cells?
Ans. a. Helper T cells
- Cytotoxic T cells
- Memory T cells
- Regulatory T cells earlier called as Suppressor T cells.
Q6. What are Toll like receptors?
Ans. Toll like receptors are transmembrane receptors which are expressed in sentinel cells such as macrophages, dendritic cells etc. Human toll like receptors was first reported by Nomura and colleague in 1994.
Q7. Which immune response is considered as the first line of defense without antigenic specificity?
Ans. Nonspecific/Innate Immune Responses
Q8. What are the cellular components of nonspecific immune responses?
Ans. Neutrophils, macrophages, dendritic cells and natural killer (NK) cells.
Q9. What is the humoral component of nonspecific immune responses?
Ans. Complement system.
Q10. What are the cellular and humoral component of specific immune responses?
Ans. Cellular component is T-cells and humoral component consists of antibodies formed by B-cells.
📌 MULTIPLE CHOICE QUESTIONS MCQs
💡Macrophages are:
A. Modified monocytes
B. Modified neutrophils
C. Modified lysosomes
D. None of the above
Answer : A
💡Macrophages are:
A. Neutrophils
B. Basophils
C.Eosinophils
D. Monocytes
Answer : A
💡 Following are the chemotaxins for neutrophil except:
A. Platelet activating factor
B. IL-1
C. IL-6
D. IL-8
Answer : C
💡 Coating of microbes with host proteins facilitating phagocytosis:
A. Chemotaxis
B. Opsonization
C. Neutralization
D. None of the above
Answer : B
💡 Integrin β2 subunit (CD18) lacks in:
A. Leukocyte adhesion deficiency II
B. Leukocyte adhesion deficiency I
C. Papillon-Lefevre syndrome
D. Agranulocytosis
Answer : B
💡 Osteoclast activating factor is:
A. IL-1
B. IL-4
C. IL-8
D. None of the above
Answer : A
💡 Pan-receptor defect of neutrophil is found in:
A. Refractory periodontitis
B. NUG
C. Adult periodontitis
D. Localized juvenile periodontitis
Answer : D
💡 Which of these immune cells forms antibodies:
A. Macrophages
B. PMNs
C. B lymphocytes
D. T lymphocytes
Answer : C