Which of the following type of immunity is present at the time of birth and is a non-specific type of defence in the human body?

The correct answer is Innate Immunity

Explanation:

• Immunity refers to the ability of the body to resist harmful microorganisms or toxins and protect against diseases.
• There are two main types of immunity in the human body: innate immunity and acquired immunity.
  • Innate immunity is present from birth and provides non-specific defense mechanisms against pathogens.
  • Acquired immunity develops during an individual's lifetime and is specific to particular pathogens.
• Innate immunity is the body's first line of defense against infections and is present at the time of birth.
• It does not target specific pathogens; instead, it provides a general defense against all harmful microorganisms.
• Components:
  • Physical barriers such as skin and mucous membranes prevent the entry of pathogens.
  • Physiological barriers include acid in the stomach, saliva in the mouth, tears from eyes–all prevent microbial growth.
  • Cellular components such as certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes.
  • Cytokine barriers: Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection. 

Other Options:

• Acquired Immunity:
  • This type of immunity develops after exposure to specific pathogens.
  • It involves the production of antibodies and memory cells, making it pathogen-specific.
  • It is characterised by memory.
• Cell-Mediated Immunity:
  • This is a type of acquired immunity where T-cells (a type of white blood cell) play a central role in defending against intracellular pathogens, such as viruses and some bacteria.
• Humoral Immunity:
  • This is another type of acquired immunity where B-cells produce antibodies to target specific pathogens. Like cell-mediated immunity, it is specific and develops after exposure to pathogens