1. An investigator performed cytofluorimetric (FACS) analyses of a mouse strain called C.B20 and a spontaneously arising point mutant that arose in the same strain called "C.B20 scid." Splenocytes from each strain were stained with anti-IgM (green) and anti-CD3 (red), then analyzed. The proportion of cells falling into each phenotypic category defined by these markers were then assessed.
|
STRAIN
|
IgM-CD3-
|
IgM+CD3-
|
IgM-CD3+
|
|
C.B20
|
5
|
60
|
35
|
|
C.B20 scid
|
98
|
0
|
0
|
The table below shows the results from all possible donor-recipient combinations of skin grafts between C.B20, C.B20 scid and another, genetically disparate strain called C57BL. Each kind of graft was done on ten mice.
Proportion of grafts surviving after 30 days
|
DONOR
|
RECIPIENT
|
|
|
C.B20
|
C.B20 scid
|
C57BL
|
|
C.B20
|
100%
|
100%
|
0%
|
|
C.B20 scid
|
100
|
100
|
0
|
|
C57BL
|
0
|
100
|
100
|
• From the first table, what do you conclude about the scid mutation?
• From the second table, what do you conclude about the mechanism of graft rejection?