J. W. TEMPLETON, A. L. ROGERS AND W. S. FLETCHER 
1077 
tween 73 pairs of 268 pairs of sibs tested.^" It 
was concluded from these data that the dog had 
a single major histocompatible locus, termed 
the DL-A locus, by the following reasoning : 
A. The data indicated that antigens re- 
sponsible for reactivity in MLC are 
controlled by genes at one chromo- 
somal locus. 
B. Reactivity in MLC correlates with the 
results of matching by certain cji;o- 
toxic antisera.i^ 
C. These same cytotoxic antisera recog- 
nize strong histocompatible antigens. ^'^^ 
D. Testing by MLC and cytotoxic antisera 
is useful in matching dogs for trans- 
plantation of marrow,^'^^ kidney,^2,i4 
liver,^^'^^ and heart.^'^ 
The preliminary studies to test various meth- 
ods of selecting dogs to breed in order to pro- 
duce DL-A matched littermates showed that 
the matching of parents by MLC and cytotoxic- 
ity was the most efficient (see Table IV). Litter- 
mates born of parents matched by both MLC 
and cytotoxicity were all nonreactive in MLC 
but littermates that were born of parents 
matched with cytotoxicity alone were nonreac- 
tive 81% of the time. Littermates that were the 
result of three generations of inbreeding were 
60% nonreactive in MLC. Based on these data 
it was concluded that the planned direct selec- 
tion on histocompatible antigens should make 
the breeding of a histocompatible dog success- 
ful and reduce the amount of inbreeding nor- 
mally required. 
Due to the promising results of the prelimi- 
nary study of direct selection on DL-A antigens 
for producing DL-A matched littermates, it 
was decided to assemble two lines of dogs for 
Table IV. — MLC results of littermates from parents 
selected by various methods 
Number Per cent 
of MLC 
Pairs Relationship Identical > 
314 Unrelated 0 
268 Sibs from unrelated parents ._. 27 
50 Sibs with inbreeding coefficients of 45% 60 
32 Sibs from sero-type identical parents 81 
30 Sibs from sero-type and MLC identical 
parents 100 
» Indicates a greater degree of histocompatibility. 
Prom: Templeton and Fletcher. Surgical Forum 22:263-264, 1971. 
Table V. — Lines I and II DL-A and Swisher Red Cell 
Antigen Phenotypes 
Line I ( 
[Chocolate Coat Color) 
Line II 
(Black Coat 
Color) 
Swisher 
Swisher 
Blood 
Blood 
Male 
U L.- A 
Groups 
Male 
OLi—A 
Groups 
1004 
BeFG 
AiC 
5215 
ACFG 
AiC 
Females 
Females 
AiC 
7229 
BeFG 
AiC 
5391 
ACFG 
9665 
BeFG 
AiC 
5394 
ACFG 
AiC 
10050 
BeFG 
AiC 
9571 
ACFG 
AiC 
9662 
BeFG 
A2C 
9689 
ACFG 
AiC 
7125 
BeFG 
AiC 
10264 
ACFG 
AiC 
10241 
BeFG 
AiC 
10265 
ACFG 
AiC 
10242 
BeFG 
AiC 
10266 
ACFG 
AiC 
further inbreeding and selection. The two lines 
are presently composed of breeders with the 
lymphocyte antigen phenotypes BeFG (Line I) 
and ACFG (Line II) (see Table V). The lines 
are composed of 1 sire and 7 bitches which all 
have the same lymphocyte antigen phenotype 
and are all nonreactive in MLC. The first litter 
born in one of these lines is currently 4 months 
of age. At six months of age the littermates will 
be tested by cytotoxicity, MLC and histogenic- 
ally by skin allografting. Selection of future 
breeder replacement for Lines I and II will be 
based on the results of this testing. 
SUMMARY 
One-way mixed leukocyte culture (MLC) and 
ten canine antisera have been utilized for select- 
ing dogs for further inbreeding and organ allo- 
grafting. The application of these techniques in 
this colony has given the following results : 
1. The determination of a single major 
histocompatible locus in dogs (DL-A). 
2. The matching of dogs for breeding with 
litters being produced that are all 
matched at the DL-A locus. 
3. A program to produce new lymphocyte 
isoantiserums has resulted in the pro- 
duction of two new antiserums which 
appear to have narrow specificities. 
REFERENCES 
1. Yager, R. H. Summary of questionnaire from Na- 
tional Research Council on number of animals used 
for research in 1969. Letter dated October 22, 1970. 
2. Starzl, T. E., Brettschneider, L., Martin, A. J., 
Groth, C. G., Blanchard, N., Smith, G. V., and 
Penn, I. Organ transplantation, past and present. 
