Regulation of the immune responses

1. IMMUNOLOGY
TOPIC : REGULATION OF IMMUNE
RESPONSE
GROUP MEMBER : ROSE MEHAK
HAMID GHUMMAN
EMAN FATIMA

2. INTRODUCTION
Effective immune response is the outcome of the interaction between antigen and
immune cell .
The functions of normal immune system
. Elimination of foreign antigens
. Tumor servillance
. Repair of tissue injury / damage

3. Immune response is subject to a variety of control mechanisms to restore the
immune system to a resting state when it is not required .
Regulatory mechanisms may act at the various phases of immune response such
a recognition , activation or effector phase .
Immune response must be regulated to allow sufficient response to protect host
from excessive or inappropriate responses that may create disease .

4. FACTORS
INFLUENCING
THE IMMUNE
RESPONSE
 Antigen (Ag)
 Lymphocytes
 Cytokines
 Antigen presenting cell (APC)
 Ideotype Network
 Circulating antibody
 Genetic
 Age

5. REGULATION BY ANTIGEN
 T-cells and B-cells are activated by antigen after successfully activating their
antigen – specific receptors .
 In the case of the T cell , the engagement is not antigen itself but of processed
antigenic peptide bound to MHC class 1 and class 11 molecules .
 Following triggering , T cell responds by producing cytokines and their
corresponding receptors , thus permitting clonal expansion and expression of
effector function .
 In the case of the B-cell , cytokine receptor expression , clonal expansion and
differentiation also occur as a consequence of triggering .

6. In the case of the B-cell , cytokine receptor expression , clonal
expansion and differentiation also occur as a consequence of
triggering .
DOSES OF ANTIGEN
. High doe of Ag _ tolerance / adverse effect
. Low doe _ tolerance
. Intermediate dose _ immunity

7. LYMPHOCYTES
Lymphocytes are B and T cells , white blood cell that produced from the stem cells in the
bone marrow . They provide immunity for future invasions of bacteria , viruses , and parasites
by producing antibodies , which have memory and will protect againt such antigen .
Helper T cells
. Release of cytokine to stimulate other immune cells
. Facillitate humoral immunity through B cells activation
. Facillitate cell-mediated immunity through cytotoxic T cells and macrophages activation

8. ANTIGEN PRESENTING CELLS (APCs)
. Antigen presentation by professional APC such as dendritic cell , macrophage and B
cells will stimulate T cell activation .
. Ag presentation by non – professional APC such as resting B cell , fibroblast and
keratinocytes will induce tolerance .
. Lack of co – stimulatory molecules required for T cell activation , including CD40 and
B7 .

9. AGE
. Very ytoung individuals do not respond to many antigens
. Elderly demonstrate diminution of immunocompetence
. Fetus may respond with IgM to some antigen
. Immunocompetence develops a few months after birth

10. CIRCULATING ANTIBODY
Circulating antibody inhibits immune response by competing for antigen with the
antibody on naive B cells , which are in low concentration , may never see in the
antigen .
Example : circulating maternal antibody interferes with childhood vaccinations in kid
under a year , so the MMR vaccine is not given until 1 year .

11. THANK YOU