D’YOUVILLE COLLEGE
BIOLOGY 108/508 - HUMAN ANATOMY & PHYSIOLOGY II
LECTURE # 14
BLOOD IV
IMMUNOLOGICAL PROPERTIES OF TISSUES
7.
Blood Groups:
• antigens (agglutinogens) on surface of all red blood cells constitute
numerous groups; two clinically important systems:
i. A-B-O system (see below) (table 17 - 4)
ii. Rh system (see below)
• cells of these two systems may induce serious immune response when
introduced into incompatible host (transfusion reaction: clumping of cells
(agglutination), complement fixation, hemolysis, possible kidney failure)
Type
Antigen
Antibody
Donor for
Recipient of
A
B
AB
O
A
B
A&B
none
anti - B
anti - A
none
anti-A/anti-B
A, AB
B, AB
AB only
all types*
A, O
B, O
all types**
O only
* universal donor
** universal recipient
Type
Antigen
Antibody
Donor for
Recipient of
Rh+
Rh-
Rh factor
none
none
anti - Rh
________
________
__________
__________
8.
Blood Typing:
a. Commercial Antisera: serum preparations containing concentrated
amounts of anti-A, anti-B or anti-Rh (anti-D) mixed with blood sample cause
clumping if corresponding antigen is present (fig. 17 - 16)
b. Cross Matching: donor cells mixed with recipient serum; donor serum
mixed with recipient cells; if no clumping, transfusion is safe
9.
Erythroblastosis Fetalis:
• Rh- woman marries Rh+ man; in many such unions, one-half of the
offspring may be Rh+ and potentially incompatible with the pregnant mother
• first pregnancy, usually, is uneventful; mother is immunologically naive
toward Rh factor; no fetal cells normally cross placenta until parturition
Bio 108/508
lec. 14 - p. 2
• inevitable mixing of maternal and fetal blood at birth introduces Rh
factor into mother’s system
• mother’s immune system becomes sensitized to Rh (she begins
producing anti-Rh)
• in second and later Rh+ pregnancies, anti-Rh antibodies (IgGs) will
cross placenta into fetus and destroy its cells producing a serious hemolytic
anemia (erythroblastosis fetalis)
• timely clinical intervention circumvents the problem: anti-Rh
administered within 72 hours of Rh+ birth destroys fetal cells in maternal system
before she has a chance to become sensitized
10.
Histocompatibility Antigens and Graft Rejection:
• antigens on surfaces of nucleated body cells are called
histocompatibility antigens (MHC proteins); produced in wide range of variants
by major histocompatibility complex (MHC) of genome
• like blood group antigens, MHC proteins on incompatible graft tissue
elicit immune response from recipient resulting in graft rejection (by CMI); four
types of tissue grafts (in descending order of capability of surviving rejection):
- autografts (derived from self); isografts (derived from genetically
identical person -- twin); allografts (derived from some other person); xenografts
(derived from different species, e.g., pig heart) (pp. 792 - 793)
• tissue typing seeks to match donor and recipient tissues for strongly
reacting MHC
• graft recipients are treated with immunosuppressants to delay immune
response to incompatible weakly reacting MHC, permitting graft to become
established; patient is at high risk during this time and must be maintained in
aseptic environment