Vaccination and Immunity

An antibody is a type of proteinaceous substance produced by the body's immune system when it detects harmful substances called antigens. Examples of antigens include microorganisms (bacteria, fungi, parasites and viruses) and chemicals. Each type of antibody is unique and defends the body against one specific type of antigen.

During an active immune response, the body can produce a massive number of antibodies to combat pathogens. The estimate of 20 trillion is generally cited in immunological literature regarding the total number of antibody molecules produced daily.

Immunoglobulin A is an antibody that plays a crucial role in the immune function of mucous membranes. The amount of IgA produced in association with mucosal membranes is greater than all other types of antibody combined. It is the main immunoglobulin found in mucous secretions, including tears, saliva, sweat, colostrum and secretions from the genitourinary tract, gastrointestinal tract, prostate and respiratory epithelium. It is also found in small amounts in the blood. Hence it provides immunity to the digestive tract as it is made up of a mucous membrane.

A. Anti-snake venom is made by collecting venom from the snake and injecting small amounts of it usually into a horse. The antibodies that form in the horse blood are then collected and used to treat a snake bite case by injecting directly to the affected person.
B. Antibodies against smallpox are produced by B-lymphocytes.
C. Antibodies contain 2 light chains and 2 heavy chains.
D. Rejection of a kidney graft is a function of T-lymphocytes.

Active immunity is the antibody response produced by the body when exposed to pathogens, vaccines etc. It is a long lasting immunity and has no side effects as these are WBCs produced by the body. 

The immunosuppressive drugs are given to treat individuals with autoimmune disorders and to suppress immunity in order prevent host immune responses against antigens on the transplanted organ, thereby avoiding rejection. There are various kinds of immunosuppressive drugs; some drugs like Calcineurin inhibitors act on some of the immune cells which synthesize the receptors for antigen binding. None of the immunosuppressive drugs acts against antigens. However, use of the immunosuppressive drugs pose a risk of infection because they don't specifically inhibit certain cells that cause autoimmunity or transplant rejection, they inhibit the entire immune system making us vulnerable to infections. Thus, the correct answer is option D.

Researchers have utilized plant-based platforms to develop vaccines for various viruses, including Zika, by expressing viral proteins in plants.

Antibodies are specialized proteins produced by B-lymphocytes within the human body as part of the adaptive immune response to identify and neutralize pathogens.

Antibodies are small proteinaceous substance made by the immune cells. Antibodies attach to proteins and other chemicals in the body, which they recognise to be not normally found in the body ('foreign'). The foreign proteins and chemicals that antibodies attach to are called as antigens. Thus, the correct answer is option A.

Explanation: Oral cholera vaccines provide only short-term immunity, which lasts for around 2 to 3 years.

All the above options are functions of local bodies. The local bodies act at the level of cities, towns and large villages.

Passive immunity is the transfer of active humoral immunity of ready-made antibodies (exogenous). Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta, and it can also be induced artificially when high levels of antibodies specific to a pathogen or toxin are transferred to non-immune persons through blood products that contain antibodies.

Active immunity is the induction of immunity after exposure to an antigen. Antibodies are created by the recipient and may be stored permanently due to the activation of memory cells which recognizes the same antigen in future and destroy them. Active immunity can occur naturally when a microbe or other antigen is received by a person who has not yet come into contact with the microbe and has no pre-made antibodies for defence. The immune system will eventually create antibodies for the microbe, but this is a slow process.

Antivenum which is injected to body in case of snakebite, contain antibodies that disable a particular venom's toxins. Antivenom is less able to reverse the damage already happened in the body. So, quick injection is a must. So, the statement A is correct.