Immunology

Question 1

3 Functions of b lymphocytes

Answer 1

1-B lymphocytes: which have the following functions:

(a) Direct antigen recognition.
b) Differentiation into Ab-producing plasma cells. (c) Antigen presentation within Class II MHC.

Question 2

T cell subsets

Answer 2

T cells subsets:

a) Helper T-cells (Th): Recognizes antigen presented within Class II MHC and promotes differentiation of B-cells and cytotoxic T-cells. b) T regulatory cells (Treg): Suppress the immune response
c) Cytotoxic T-cells (Te): Recognize antigen presented within class I MHC and kills cells expressing appropriate antigen

Question 3

Macrophage function

Answer 3

a) Enhances phagocytosis.
b) Antigen presentation within Class II MHC.

C- produce il1 that stimulate t cell proliferation and differentiation

Question 4

What are killer cells

Answer 4

Natural Killer (NK) cells: Kills variety of target cells (e.g. tumor cells or viral infected cells
 2- Killer (K) cells: Bind Fe portion of immunoglobulin. Kills antibody-coated target cells.

Question 5

Cytokines effect

Answer 5

Cytokines are soluble proteins produced by many cells, and are critical to the functioning of both innate and adaptive immune responses.

Effects:

1. Each cytokine binds to a specific cell-surface receptor.
2. Subsequent intracellular signalling cascades then alter cell functions.
3. This includes the upregulation and/or downregulation of several genes that result in production of other cytokines, or increase in the number of surface receptors for other molecules, or suppress their own effect by feedback inhibition.

Question 6

Immunoglobulin fragments

Answer 6

Fab antigen binding one

Fc - the remainder of the 2 heavy chain

Question 7

Conc. and function of ig

Answer 7

-IgA
3.5mg/ml
Mucosal immunity
-IgD
Trace
On naive b cells (bcr)
-igE
.05
Defence against parasites
Immediate hypersensitivity
-igG
13.5
Opsonisation
2ry immune response
Complement activation
ADCC
-igM
1.5
1ry immune response
Naive b cell receptors
Complement activation

Question 8

Rce of complemnts protiens and their availability in body fluids

Answer 8

-macorphages
Intestinal mucosa
Liver
------------------------------------
In serum and extracellular fluid
Not in urine or csf

Question 9

Functions and role of complement

Answer 9

:

Immunology

1- Lysis of cells, bacteria and enveloped viruses. 2- Opsonization, which prepare for phagocytosis.

3- Regulation of immune and inflammatory responses.

4- Regulation of the biological activity of cells as chemotaxis and cell adhesion.