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Disorders of the Immune System. Autoimmune Disorders – body produces antibodies against its own tissue, e.g. Grave’s disease (hyperthyroidism) and rheumatoid arthritis Allergies occur when the body reacts to materials which should not be antigenic, e.g. peanuts. Immunity. Passive immunity - PowerPoint PPT Presentation
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Disorders of the Immune System
• Autoimmune Disorders – body produces antibodies against its own tissue, e.g. Grave’s disease (hyperthyroidism) and rheumatoid arthritis
• Allergies occur when the body reacts to materials which should not be antigenic, e.g. peanuts
Immunity
Active immunityProduction of a person’s own
antibodies; long lasting
Passive immunityAn individual is given antibodies by
another ; short-term (weeks- 6 months)
Natural ActiveWhen pathogen
enters body in the normal way, we make antibodies
Natural PassiveFrom mother in
uterus & breast milk
Artificial PassiveImmunoglobulin
injection;extremely fast, but
short lived (e.g. snake venom)
Edward Jenner
Artificial ActiveVaccination – person makes
antibodies without becoming ill
Blood Groups & Immunology
The ABO System
• Discovered in 1901 by Dr. Karl Landsteiner
• 4 main phenotypes (A, B, AB, O)
• Type of inheritence: multiple alleles (each person has only 2 alleles but more than 2 alleles exist)
• Three possible alleles: IA, IB, i
Phenotype vs. Genotype
Phenotype Genotype
A IA IA or IA i
B IB IB or IB i
AB IA IB
O i i
Inheritance of ABO Groups
If the mother has blood type O and her husband is blood type AB, what will be the blood type of their baby?
IA i IA i
IB i IB i
i i
IA
IB50 % chance A blood type
50 % chance B blood type
Distribution of the A allele
Distribution of the B Allele
Distribution of the O Allele
Universal Donor and Recipient
Universal Donor
• Group O
– Carries no A or B antigens
Universal Recipient
• Group AB
– No anti-A or anti-B present
The Rh(D) System
• Discovered in 1940 on Rhesus monkeys
Simple Genetics of Rh(D)
• 86% of caucasians are Rh(D) positive• The d gene is recessive:
– DD & Dd persons are Rh(D) pos– Only dd persons are Rh(D) neg
Distribution of Rh(D) Types
Population Rh(D) pos Rh(D) neg
Caucasian 86% 14%
African-American 95% 5%
Oriental >99% <1%
Significance of Rh(D)
• Rh(D) negative persons exposed to Rh(D) pos blood will develop anti-D
• Anti-D can also be stimulated by pregnancy with an Rh(D) positive baby– Can be prevented by the use of anti-D
immunoglobulin (RhoGam shot) administered before and after childbirth
Inheritance of ABO and Rh(D)
Mother
Group A IA i
Rh(D) pos Dd
Father
Group B IBi
Rh(D) pos Dd
Draw a Punnet Square for this DIHYBRID CROSS; show phenotypic ratios.