Tag: immunity and blood groups

Artificially acquired passive immunity is a short-term immunization achieved by the transfer of antibodies, which can be administered in several forms such as human or animal blood plasma or serum. Antivenine is an antisera which is obtained from the snake poison and it is transferred to the person with snake bite. It is used to provide immediate immunity in case of emergency.

• When the immune system is activated due to the viral infection or other immune response the white blood cells in our body produces Interferons (are a group of proteins called cytokines). Interferons inhibit viral multiplication
• The name of the interferons comes from their ability to interfere with the production of new virus particles. Interferons do not directly kill viral or cancerous cells; they boost the immune system response and reduce the growth of cancer cells by regulating the activity of several genes that control the secretion of numerous cellular proteins that affect growth.
• Hence cytokine that provides nonspecific immunity against viruses is Interferon.
• So, the correct answer is 'Interferons'.

The acquired immune system, also known as the adaptive immune system is a subsystem of the overall immune system that is composed of highly specialized, systemic cells and processes that eliminate pathogens or prevent their growth. Acquired immunity creates immunological memory after an initial response to a specific pathogen, and leads to an enhanced response to subsequent encounters with that pathogen. Acquired immunity distinguish between self and non-self and produce antibodies against the non-self antigen.

Cytokines are a broad category of small proteins that are important in cell signalling. Their release has an effect on the behaviour of cells around them. Proinflammatory cytokines are produced predominantly by activated macrophages and are involved in the up-regulation of inflammatory reactions. There is abundant evidence that certain pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α are involved in the process of pathological pain.

Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. They are essential for fighting infections and for subsequent immunity. Phagocytes provide the second line of defence which is considered as a non-specific defence because it destroys invaders in a generalized way without targeting specific pathogens. Phagocytes are activated when the pathogen is able to cross the first line of defence.

Neutrophils are the most abundant type of granulocytes. They form an essential part of the innate immune system. Neutrophils undergo a process called chemotaxis via amoeboid movement, which allows them to migrate toward sites of infection or inflammation. Neutrophils express and release cytokines, which in turn amplify inflammatory reactions by allowing other neutrophils, monocytes, eosinophils attachment to endothelium and dilation of capillaries is seen to increase the blood flow to the affected area.

Chemical barriers protect against infection. The skin and respiratory tract secrete antimicrobial peptides such as the β-defensins. Enzymes such as lysozyme and phospholipase A2 in saliva, tears, and breast milk are antibacterial substances. Vaginal secretions serve as a chemical barrier following menarche, when they become slightly acidic, while semen contains defensins and zinc to kill pathogens. In the stomach, gastric acid serves as a powerful chemical defence against ingested pathogens.

Innate immunity refers to nonspecific defence mechanisms that come into play immediately or within hours of an antigen's appearance in the body. These mechanisms include physical barriers such as skin, chemicals in the blood, and immune system cells such as neutrophils that attack foreign cells in the body.  Polymorphonuclear leukocytes (PMNL - neutrophils) are the granulocytes characterized by the presence of granules in their cytoplasm. They provide innate immunity.

• Passive immunity is the transfer of active humoral immunity of ready-made antibodies (exogenous) or preformed antibodies. 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. People administered with preformed antibodies get 'Passive immunity'.
• So, the correct answer is 'Passive immunity'.

Lysozyme, also known as muramidase or N-acetylmuramide glycanhydrolase is an antibacterial enzyme produced by animals and humans that forms part of the innate immune system. Lysozyme is abundant in secretions including tears, saliva, human milk, sweat and mucus. It is also present in cytoplasmic granules of the macrophages and the polymorphonuclear neutrophils. Lysozyme is an enzyme and hence, acts as a chemical barrier of infection.