Study of immunity is k/a immunology. Immune system Role in protection are two types—innate& adaptive.

Immune system protect us form different types of antigen.

(1)Non self antigen. (2) Foreign molecules. (3) Exogenous antigens. (4)Not released to us bacteria,virus, protozoa. (5) Fungus, allergy.

INNATE IMMUNITY [by birth]:- (a)Natural immunity. (b)Inborn(from birth). (c)Non specific immunity. (d)Immediately activated but gives general protection. (e)Faster response.

COMPONENTS OF INNATE IMMUNITY:- (a)Physical barrier. (b) prevent antigen entry ,skin mucus, membrane. (c)MALT—MUCUS ASSOCIATED LYMPHOID TISSUE.

INTERNATIONAL DEFENCER CELLS:- Ex-Macrophages (phagocytosis). Dendritic cells (20lymphoid organ). Neutrophils—phagocytosis(blood). Nk cell—kill virus infected cells. Easinophills—kill parasite. Basophills— inflamation. Mast cell—type 1hyper sensitivity.

INNATE IMMUNITY:-. (1)Recognise broad pattern pathogen. (2)Innate immunity —Activate adaptive. (3)Blood proteins immunity, complement proteins. (4)Protein present inactive form. (5)Interference. (6) Released by virus infected cells. (7) Interferons activate antiviral immunity. (8)Inhabits protein synthesis of virus —recognised broad pattern pathogen. (9) Pattern recognization receptors. (10) Tall like receptors. (11)PAMP–Pathogen, associated molecular pattern. (12)DAMP–Damage associated molecular pattern. Different tall like receptors recognise different types of pattern. Ex-Peptodoglycon,lipopolysaccharides, bacterial, lipoproteins,flagella,single strand RNA,double strand Rna.

MEMORY RESPONSE:- (a)No memory cell formation. (b) Diversity in recognition of diverse antigen. (c) Active all time. (d) Present all time. No autoimmunity disorder caused due to innate immunity.

ADAPTIVE IMMUNITY:- Also k/a Acquired immunity. Recognised & selectively elimenating specific foreign antigen have four characteristics feature.

ANTIGEN SPECIFICITY:- Ability to discriminate among different antigens. Immunological memory recall the previous contents with a foreign antigen & respond to it in learn manner that is a more & large response.

DIVERSITY:-Ability to response differents antigens.

ADAPTIVE IMMUNITY:- found two types– (i) NATURAL:- organisms acquire immunity naturally two types–Active & Passive.

(a)Active :– developing his or her own antibodies after exposure to pathogen.

(b)Passive:- acquired by releasing formed immunity made by another for example: transfer of maternal antibodies from mother to fetus through Placenta.

(ii)ARTIFICIAL:-An organisms acquired immunity through medical procedurecan be k/a Artificial.

(a) Active:-Developing his or her own immunity a result of vaccination.

(b) Passive:- Acquired by resiving performed & antibodies or immune cells made by another.

The immune system is a complex network of cells, tissues, and organs that work together to protect the body from infections and diseases. One of the key components of the immune system is the cells that make it up. These cells can be broadly classified into two main types: innate immune cells and adaptive immune cells.

Innate immune cells are the first line of defense against invading pathogens. They include neutrophils, macrophages, dendritic cells, natural killer cells, and mast cells. These cells are found in various tissues and organs throughout the body and are able to quickly recognize and respond to foreign invaders. They do not require prior exposure to the pathogen to initiate a response.

Adaptive immune cells, on the other hand, are specialized cells that are able to recognize and remember specific pathogens. These cells include B cells, T cells, and antigen-presenting cells (APCs) such as dendritic cells. B cells are responsible for producing antibodies, which bind to specific antigens on the surface of pathogens, marking them for destruction by other cells of the immune system. T cells are responsible for killing infected cells and also help to activate other cells of the immune system. APCs present antigens to T cells, which then activate B cells and other T cells to initiate a specific immune response against the pathogen.

All of these cells work together to provide the body with a robust immune response against infections and diseases. The immune system is able to recognize and respond to a wide range of pathogens, and it is also able to remember previous encounters with these pathogens, providing long-term protection against future infections.


The immune system is composed of different types of cells that work together to protect the body against infections and foreign invaders. These cells are classified into two main categories: innate and adaptive immune cells. The innate immune cells are the first line of defense against pathogens, while the adaptive immune cells are activated after exposure to a pathogen and provide long-lasting protection.

Here are some of the main types of cells in the immune system:

  1. T cells: These are a type of adaptive immune cell that are responsible for recognizing and destroying infected or cancerous cells. T cells are produced in the thymus gland and are activated when they encounter antigens on the surface of other cells.
  2. B cells: B cells are also a type of adaptive immune cell that produce antibodies in response to pathogens. These antibodies bind to the surface of the pathogen and mark it for destruction by other immune cells.
  3. Natural killer (NK) cells: These are a type of innate immune cell that are responsible for killing infected or cancerous cells. NK cells are able to recognize abnormal cells based on changes in their surface proteins.
  4. Dendritic cells: These are another type of innate immune cell that are responsible for presenting antigens to T cells. Dendritic cells are found throughout the body and are able to pick up antigens from infected cells or invading pathogens.
  5. Macrophages: These are large immune cells that are responsible for engulfing and destroying pathogens and debris. Macrophages are found in many tissues throughout the body and play an important role in initiating the immune response. B-cells are a type of lymphocyte, a white blood cell that plays a key role in the adaptive immune system.

B-cell Properties

B-cells are a type of white blood cell that play a critical role in the immune system’s defense against pathogens. Here are some of the key properties of B-cells:

B-cells originate in the bone marrow: B-cells are produced in the bone marrow, where they mature and differentiate into various subsets.

B-cells express B-cell receptors (BCRs): BCRs are membrane-bound immunoglobulin molecules that bind to specific antigens. Each B-cell expresses a unique BCR that allows it to recognize a particular antigen.

B-cells undergo clonal expansion: When a B-cell encounters its specific antigen, it undergoes clonal expansion, which means it divides and produces a large number of identical daughter cells.

B-cells differentiate into plasma cells: Some of the daughter cells of the B-cell undergo further differentiation into plasma cells, which produce and secrete large amounts of antibodies.

B-cells can undergo somatic hypermutation: Somatic hypermutation is a process by which the BCR genes of the B-cells undergo mutations to increase their affinity for the antigen.

B-cells can undergo class switching: Class switching is a process by which B-cells change the class of antibody they produce from IgM to other classes such as IgG, IgA, or IgE.

B-cells can form memory cells: Some of the daughter cells of the B-cell differentiate into memory B-cells, which provide long-term immunity against future encounters with the same antigen.
T-cells, also known as T-lymphocytes, are a type of white blood cell that plays a crucial role in the immune system. Here are some of the properties of T-cells:

T-cells are formed in the bone marrow and mature in the thymus gland.
T-cells can be classified into two main types: CD4+ T-cells (helper T-cells) and CD8+ T-cells (cytotoxic T-cells).
Helper T-cells (CD4+ T-cells) help activate other immune cells such as B-cells and macrophages to attack foreign invaders.
Cytotoxic T-cells (CD8+ T-cells) directly kill infected cells or cancerous cells.
T-cells have a T-cell receptor (TCR) on their surface that recognizes specific antigens on the surface of infected or abnormal cells.
T-cells require a co-stimulatory signal from antigen-presenting cells (APCs) to become activated and proliferate.
T-cells can form long-lasting memory cells that enable a faster and stronger immune response to a previously encountered antigen.
T-cells can also play a role in autoimmune diseases, where they mistakenly attack normal cells in the body.

COMMON MYELOID PROGENITOR:- The c.m.p cell give rise [granilocytes, neutrophils,basophills,cosinophills & mast cells, monocytes, macrophages eurthrocytes & megakaryocytes.

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