The steps of a specific immune response includes: antigen recognition --> antigen presentation--> clonal expansion--> attack.
Explanation:
In the resistance of the body to infection, the human body has the ability to develop extremely powerful specific immunity against individual invading agents such as lethal bacteria, viruses, toxins and even foreign tissues from other animals. A typical example of a specific immunity is the ADAPTIVE or ACQUIRED IMMUNITY. This is defined as the immunity caused by a special immune system that forms antibodies and/ or activate lymphocytes that attack ans destroy the specific invading organisms or toxins.
There are two types of adaptive immunity which include the cell mediated immunity and the antibody mediated immunity.
The steps and the cells involved in these specific immune response includes:
--> ANTIGEN RECOGNITION: these invading organisms or agents contains one or more specific chemical compounds in its makeup that are different from all other compounds. These substances are called ANTIGENS. The T -lymphocytes and the B- lymphocytes are able to recognise and be sensitized by these antigen particles.
--> ANTIGEN PRESENTATION: These antigens need to be presented to the T- lymphocytes unlike the B- lymphocytes that bind antigen particles without having to be presented by any antigen presenting cell. Example of antigen presenting cell is the MACROPHAGES. they present the antigen to T-lymphocytes by engulfing and digesting the antigen which they transport the most antigenic fragment to their own cell membrane where it is displayed on their surface.
--> CLONAL EXPANSION: After presentation of the antigen to the T- lymphocytes, it stimulates the division and proliferation of the T- lymphocytes to produce specialised T- lymphocytes which will attack the original antigen in different ways.
--> ATTACK: After clonal expansion of T-lymphocytes the specialised T- lymphocyte cells produce initiates different attacks. These cells include:
• Memory T- cells: these long-lived cells survive after the threat has been neutralised and provide specific immunity by responding rapidly to another encounter with the same antigen.
• Cytotoxic T- cell: they directly inactivate any invading target cell and release powerful toxins.
• Helper T-cells: These cells produce special chemicals called cytokines which support and promote Cytotoxic T-lymphocytes and macrophages.
•suppressor T-cells: These cells act as 'brakes', turning off activated T- lymphocytes thereby limiting the powerful and potentially damaging effects of the immune response.
