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Types of Immunity
Case Study
Jagraj Brar
Basics
Antigen- foreign substance in the body Antibody- fight antigens:
IgA IgD IgE IgG IgM
Alpha Delta Epsilon Gamma Mu
10 Antigen binding sites.
4 antigen binding sites
2 antigen binding sites
Introduction
Immunity is the ability of the body to resist becoming infected upon exposure to any antigen.
Some various types include:-Passive immunity (Artificially & Naturally)
-Herd immunity
-Active immunity (Artificially & Naturally):Innate Acquired-Cellular immunity -Cellular immunity -Humoral immunity -Humoral immunity
Passive Immunity
Naturally Acquired- Occurs during
pregnancy,
- Certain antibodies are passed from the maternal into the fetal bloodstream
- IgG can cross the placenta
Artificially Acquired-A short-term immunization
-The injection of antibodies, that are not produced by the recipient's cells.
Herd Immunity
Protection of any one individual from a disease following the principal, that everyone around him/her is immune
Hence no direct exposure to the disease.
Virologists have found that when a certain percentage of a population is vaccinated, the spread of the disease is effectively stopped. This critical percentage, called the herd immunity threshold.[1]
[1] Jamison DT, Breman JG, Measham AR (editors) (2006). "Chapter 4: Vaccine-preventable Diseases". Priorities in Health: Disease Control Priorities Companion Volume. World Bank Publications.
Active Immunity
Naturally Acquired- Expose to live pathogen
- Development of disease
- Immunity develops due to primary immune response
2 Types:
Innate & Acquired
Artificially Acquire
-Vaccine containing antigen
-Simulates the primary immune response
-No development of disease
Active ImmunityInnate
Naturally occurring Non-Specific Immediate response Can kill many microrganisms at a time Present at birth 2 types:-Humoral-Cell Mediated
Humoral immunity(Innate)
1)Complement system
2)Interferons (prevent spread of virus)
3)Natural killer cells
MAC
Opsonization by C3b targets foreign
particles for phagocytosis
Membrane attack
complex
Interferon
Virally infected cell Non-viral infected cell
Blue= Interferon Coat
Cell Mediated (Innate)
1)Neutrophils
2)Monocytes
3)Macrophages
Active ImmunityAcquired
Specific antibodies are raised against the previous microrganism.
Can only kill microrganism one at a time. 2 Types:
Humoral – B Lymphocytes
Cell Mediated- T Lymphocytes
Humoral immunity(Acquired)
B-Lymphocytes Origin Function Types
Origin of B-Lymphocytes
The abbreviation "B", in B cell, originally stood for bursa of Fabricius in birds
Now stands for bone because in mammals, immature B cells are formed in the bone marrow
Functions of B-Lymphocytes
B-cells have IgM Antibody B-cell receptor will bind to one particular
antigen B-cell comes across antigen causes the B-
cell to receive a signal from T-helper cell to form:
Plasma B Cells OR Memory B Cells
Plasma B- Cells
Large B-cells Activated (already exposed to antigen) and
secreting large amounts of antibodies. Make microbes easy targets for phagocytes and
activation of complement system “Antibody Factories” Short lived cells which undergo apoptosis after
antigen is eliminated.
Memory B-Cells
Activated B-cells
Specific to the antigen encountered during the primary immune response
Cells are able to live for a long time and can quickly respond during a second exposure to the same antigen,
Hence the name Memory cells
c
major histocompatibility complex (MHC).
Cell Mediated Immunity(Acquired) T-Lymphocytes T=“Thymus” When come in contact with antigen, they release
cytokines which help convert t-cells into: 3 Types: Tc – Cytotoxic T Cells Th- Helper T Cells Ts- Suppressor T Cells
Clinical correlations
Autoimmune Diseases. T-cell disorders B-cell disorders Immunodeficiency (AIDS) SCID- Severe combined
immunodeficiency
Autoimmune diseases: Arise from an overactive immune response.
Body begins to attack substances and tissues that are normally present in the body
Can be restricted to certain organs or tissues or it can be in many places of the body.
Treatment is immunosupression- which is a medication which decreases the immune response.
Examples include: Lupus, Goodpastures etc.
Disorders of T cells: DiGeorge’s syndrome ABSENT, FEW OR ABNORMAL T-CELLS
Large deletion of chromosome 22.
Congenital thymic dysplasia
absence or hypoplasia of thymus, parathyroid glands
Symptoms include: heart defects, effects on facial appearance, and lack of or underdeveloped thymus and parathyroid glands.
DiGeorge’s syndromeHypertelorism MicrognathiaShort philtrumFish mouthAntimongoloid slantLow-set earsCleft palateHypocalcaemia
Treatment: Bone Marrow Transplant
Disorders of B cells: X-Linked Infantile Hypogammaglobulinemia Most severe B-cell immunodeficiency Defective BTK Gene: Tyrosine Kinase Symptoms: Decreased/Absent b-cells Decreased/Absent immunoglobulins Increased susceptibility to bacterial
infections Treatment: Bone Marrow Transplant.
SCID- Severe combined immunodeficiency
Disorders of lymphoid stem cells Defects in both humoral and cellular
mediated immunity T-cells & B-cells 1: 100,000 births Lack of lymphoid cells: thymus, peripheral
lymphoid organs Death due to infections at 1 yr of age
David Vetter: the BUBBLE BOY
References 1)"Active and Passive Immunity." Active and Passive Immunity. 2007. The
Columbia Electronic Encyclopedia, 6th ed. Copyright ©. 6 June 2009 <http://www.infoplease.com/ce6/sci/A0858765.html>.
2)"The Complement System." The Complement System. 22 Sept. 2007. 6 June 2009 <http://www.howstuffworks.com/framed.htm?parent=immune-system.htm&url=http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Complement.html>.
3)Guyton, C., and John E. Hall. The Textbook of Medical Physiology. Vol. 11. Elsevier Inc.
4)Hull, Dr. "Immunity, types of." Night, Night! Dr. Hull's Common Sense Sleep Solutions. 06 June 2009 <http://www.drhull.com/EncyMaster/I/immunity.html>.
5) [1] Jamison DT, Breman JG, Measham AR (editors) (2006). "Chapter 4: Vaccine-preventable Diseases". Priorities in Health: Disease Control Priorities Companion Volume. World Bank Publications.
6) Dr. Prasad. Immune system classifications. Pre-Med 2- Physiology. 2008.