BT302 Final Term Mega File by Biotech Brainy Bunch

CURRENT FINAL PAPER SPRING 2022

1. Affinity maturation

The affinity of antibodies depends upon the dosage of antigen, the low dosage of antigen causes increase in the affinity of antibodies which is called as affinity maturation.

A secondary response can elicit antibodies with several fold greater affinity than in a primary response. Affinity maturation primarily occurs on membrane immunoglobulin of germinal center B cells and as a direct result of somatic hyper mutation (SHM) and selection by T cells.

2. Antibodies types

There are 5 types of heavy chain constant regions in antibodies (immunoglobulin) and according to these types; they are classified into IgG, IgM, IgA, IgD, and IgE. They are distributed and function differently in the body.

3. AIDS (10)

Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight infection and disease.

HIV is a sexually transmitted infection (STI). It can also be spread by contact with infected blood and from illicit injection drug use or sharing needles. It can also be spread from mother to child during pregnancy, childbirth or breastfeeding. Without medication, it may take years before HIV weakens your immune system to the point that you have AIDS.

Symptoms · BT302 - FINALTERM SUBJECTIVE MEGA FILE · GROUP: BIOTECH BRAINY BUNCH · ALL DATA FROM PAST PAPERS · ADMINS: MEHWISH MUGHAL & BELLA

The symptoms of HIV and AIDS vary, depending on the phase of infection.

Causes

HIV is caused by a virus. It can spread through sexual contact, illicit injection drug use or sharing needles, contact with infected blood, or from mother to child during pregnancy, childbirth or breastfeeding.

4. Alternate pathway (10)

The alternative pathway is a type of cascade reaction of the complement system and is a component of the innate immune system, a natural defense against infections. The alternative pathway is one of three complement pathways that opsonize and kill pathogens. The pathway is triggered when the C3b protein directly binds a microbe. It can also be triggered by foreign materials and damaged tissues.

Functions of Complement Proteins

Complement system provides specific as well as non-specific resistance against infections. This kind of resistance is exhibited with following two important functions

Primary function

This function of complement proteins is considered primary as these activated proteins used to kill or lyse infectious agents like bacteria. For this complement proteins get deposited on the surface of infectious agents which make hole in those cells for their lysis or killing.

Secondary or Effector functions

These functions of complement proteins effect on other functions of immune system.

Complement Activation

Complement proteins are activated through a series of cascading reactions which are called as complement activation. Followings are the important pathways for complement activation

1. Classical Pathway
2. Alternate Pathway
3. Mannose Bindning Lectin (MBL) Pathway

These pathways generate the activated form of complement like C5 which leads towards a pathway called as common pathway as a result the membrane attack complex is generated for the lysis of microorganism.

5. Cellular immunity

Cellular mediated immunity provides protection by following ways:

T-cell immunity

In this form of protection, cytotoxic T-cells (CTL) are activated for the killing of infected and transformed cells.

By activating macrophages

By this way, macrophages are activated for destroying various pathogens.

By activating natural killer (NK) cells

In this way of protection, NK cells are activated for killing of transformed and viral infected cells.

Q6. Name of barriers against infection pathogens?

Innate immune system is the first line of defense against invading pathogens. It is comprised of following three important components or barriers

1. Anatomical barriers
2. Humoral (Secretory) barriers
3. Cellular barriers

7. Somatic Hyper mutation (2)

Somatic Hyper mutation

The phenomenon of enhanced rate of point mutation in the immunoglobulin V region genes is called as Somatic hyper mutation. It occurs particularly in V gene which codes for 2nd hyper variable region. As a result, there is an increase in immunoglobulin diversity after various antigenic stimulation. Moreover, it also causes increase the affinity of immunoglobulin in order to compete for limited amount of available antigens.

8. Application of agglutination reaction (3)

Application of agglutination reactions

Agglutination reactions are used for following ways

Blood group determination: ABO & Rh for both either on the basis of antigens of RBC or antibodies of serum Assessing bacterial infections e.g Widal test for diagnosis of Typhoid fever

9. Define onco-fetal antigen and it's types (3)

The tumor antigens which are also expressed by normal cells. These are expressed in high levels by tumor cells as compare to normal cells. These kinds of antigens are also called as onco-fetal antigens as these are expressed during early development & lost during adult life. However, these antigens re-expressed on tumor cells. These antigens also serve as tumor markers due to their importance in the diagnosis & prognosis of cancers