Health unit 1

 Part 4

Types of acquired immunity----

 There are two types of acquired immunity are as follows:-

1. Active immunity

2. Passive immunity

1. Active immunity (natural)

It is induced by natural exposure or by vaccination.

#  Humoral immunity

* it is defined as immunity mediated by antibodies, which are secreted by B lymphocytes.

* B lymphocytes secretes antibodies into blood and lymph.

* Blood and lymph are the body fluids. Since B lymphocytes provide immunity through hormones,so this immunity is called humoral immunity.

* Humural immunity is the measure defence mechanism against bacterial infection.

# Cell mediated immunity

* also called cellular immunity or T - cell immunity

* It is defined as the immunity develop by cell mediated response.

* It involves several types of cell's such as T lymphocytes, macrophages,nature killer cells, hence name cell mediated immunity

* Cell mediated immunity does not involve antibodies 

* cell mediated immunity is offered by T lymphocytes and it starts developing when T cells come in contact with antigen

∆  Live Vaccine

BCG for tuberculosis

MMR for measles ,mumps, rubella

Sabin vaccine for Polio mellitus

 ∆ Killed Vaccine

Inactivated polio vaccine

Pertusis (whooping cough)

2. Passive immunity 

It is the immunity that is transferred to recipient in redimate form.

Natural passive immunity

This immunity last for short period of time.

E.g. transport from mother to foetus through placenta.IgG ( immunoglobin), cross placenta to reach foetus.

Artificial passive immunity

Immunity transferred passively by administration of antibodies.

Difference between active immunity and passive immunity

 Active immunity                     Passive immunity

1. Produced by bodies      1.  received passively by  own immune system                                                                                               host,no                                                                                 involvement of                                              immune system.

2. Active immunity is         2. It is short lasting

long lasting

3. More affective              3. Less affective

4. Offer better protection   4. Inferior protection