Question

In higher vertebrates, the immune system can distinguish self-cells and non-self. If the property is lost due to genetic abnormality and it attacks self-cells then it leads to
A. Allergic response
B. Graft rejection
C. Auto-immune disease
D. Active immunity

Answer 1

Hint: Our body has the ability to defend itself from most of the foreign agents. This ability of the host is referred to as immunity. Immunity is of two types: a) Innate immunity and b) Acquired immunity. Based on the ability of differentiating pathogens (foreign organisms) from self-cells, higher vertebrates became familiar with memory-based acquired immunity.

Complete answer:
> Paul Ehrlich realized that the immune system instead of reacting against foreign antigens can sometimes attack self-antigens.
> This results in an inappropriate response of the immune system against self-components termed as autoimmunity.
> Auto-immunity leads to damage in our body referred to as auto-immune diseases.
> Normal healthy individuals possess mature self-reactive lymphocytes.
> A breakdown in the regulation of these self-reactive lymphocytes leads to the activation of self-reactive clones of T or B cells.
> As a result, humoral or cell-mediated responses are generated against self-antigens.
> Cells and organs can be seriously damaged by these reactions. Sometimes they may have fatal consequences.
> Sometimes, the damage to self-cells or organs is caused by antibodies and in other cases, T cells are the culprit.

In higher vertebrates, the immune system can distinguish self-cells and non-self. If the property is lost due to genetic abnormality and it attacks self-cells then it leads to ( C ) Auto-immune disease.

Additional information: -
> Paul Ehrlich termed this condition a horror auto-toxicus.
> Rheumatoid arthritis which affects many people in our society is an example of auto-immune disease.
> Each antibody molecule consists of four peptide chains. Out of the four chains, two small are called light chains and two longer chains are called heavy chains.

Note: While innate immunity is a non-specific type of defense, acquired immunity is pathogen-specific.
B-lymphocytes mediate the humoral immune response.
T-lymphocytes mediate the cell-mediated immune response.