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 immunity
Production of a person’s own
antibodies; long lasting
Natural Active
When pathogen
enters body in the
normal way, we
make antibodies
Passive immunity
An individual is given antibodies by
another ; short-term (weeks- 6 months)
Artificial Active
Natural Passive
Vaccination –
From mother in
person makes
uterus & breast milk
antibodies without
becoming ill
Edward Jenner
Artificial Passive
Immunoglobulin
injection;
extremely fast, but
short lived (e.g.
snake venom)
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
ii
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?
50 % chance A blood type
50 % chance B blood type
i
i
IA
IA i
IA i
IB
IB i
IB i
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
Father
Group A IA i
Group B IBi
Rh(D) pos Dd
Rh(D) pos Dd
Draw a Punnet Square for this DIHYBRID CROSS;
show phenotypic ratios.