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Human chorionic gonadotropin and skin homograft survival
CURRENT INVESTIGATION
Human chorionic gonadotropin skin homograft WARREN
H.
HAROLD
KAIMAN,
Omaha,
and
surv’ wal
PEARSE,
B.S.. B.S.,
M.D. M.D.
Nebraska
Rejection of Jkin homografts days to an average of 13.3 human chorionic gonadotropin. a homograft is discussed.
in immature mice war delayed days by the daily intraperitoneal Possible relationship to the
?'H E R E AS 0 N s for the in utero survival of mammalian pregnancy, a homograft, are of key importance in the understanding of reproductive physiology, as well as the entire tissue transplantation problem. Excellent reviews of the subject include those of Billingham1 and Lanman.” Of the four protective mechanisms usually suggested as responsible for pregnancy survival, natural and animal experimentation has shown that nonantigenicity of the fetus and the uterus as a privileged transplantation site are not valid reasons. Both the trophoblastic “barrier” and lowered reactivity during maternal immunologic pregnancy are related to fetal homograft survival, but neither offers the entire explanation, and the modes of action of both are not completely clear. From the Department Gynecology, Uniuersity College of Medicine. Supported in Public Health ROI-AMA-l-09288 2TI-HD-18.
Part by Service
of Obstetrics of Nebraska United
Grant
and
A “iibrinoid” barrier around individual trophoblastic cells has been suggested as responsible for their nonantigenicity,3 but recent electron microscopic studies have not demonstrated this layer.+ Nelson and associates5 described the effects of HCG and HCG plus estrogen on the thymolymphatic system in rats. With HCG in doses extrapolated from human pregnant levels there was a significant weight reduction in the thymus, but no weight changes in the spleen, lymph nodes, or intestinal lymphoid masses. With HCG plus estrogen, acute atrophy of the thymus occurred. Serr. Hiran, and Neumanc studied the effects of cortisone. estrogen, HCG, progesterone, a combination of estrogen, progesterone, and HCG, and normal pregnancy on the survi\,ai of full thickness skin homografts in mice. There was a progressively increased survival of the grafts compared to controls in the order listed, with the longest survival (a time increase of 87 per cent’) occurring in pregnancy. Because HCG is unique to the pregnant
and
States
Training
from an average of 11.3 injection of 200 I.U. of problem of pregnancy as
Grant
572
Volume Number
98 4
HCG
state; the dosage of HCG used relatively lo\~-50 I.U. in 30 and pregnancy itself produced homograft survival than the hormones, we elected to begin pression studies with HCG. Materials
and
by Serr was gram mice; a longer use of any immunosup-
Table I. Number Day
8 9 10 II
skin
homograft
of new
survival
573
rejects
Cor1trol
1 9
/
With HCG 2 1 1 5 4 8 9
13 14 15 16
7 3 IO 1 5 2 1
Total
:19
44
13.3 days 2.23 error cf difference
11.3 days 2.09 0.475
12
methods
Ninety immature female mice of the congenic resistant strain B,, D, and 5 female mice of the inbred partner strain C57BL/lO SC Sn (H-2 in compatability) were obtained from the Jackson Memorial Bar Harbor. They weighed Laboratories, approximately 15 grams each. The technique of grafting was as follows: 1. Depilate mice from scapula to tail with Nair one or 2 days before grafting. 2. Kill donor mouse (C57BL/lO SC Sn). 3. Remove tail skin of donor by circular incision with a No. 21 Bard-Parker blade, pulling skin toward caudal end. 4. Place tail skin in Petri dish with filter paper bottom, and float in sterile saline. 5. Wash blood from tail skin. 6. Cut skin to appropriate size (about 3 ‘9: 4 mm.) . 7. Anesthetize depilated mouse, and secure on animal board. 8. Swab depilated area with 70 per cent alcohol. 9. With forceps, pinch skin in middle of back and raise. With a No. 15 Bard-Parker blade remove a 3 x 4 mm. area of raised skin down to panniculus carnosus. 10. Place donor skin rapidly on dry filter paper and then on graft recipient area. 11. Dust graft area with Neosporin Powder and tape with Elastiderm tape. Mice were randomly removed from their cages and numbered by marked tape. Odd numbered mice were grafted only. Even numbered mice were grafted and received 200 I.U. of HCG intraperitoneally daily, beginning on the day of the graft, and continuing until rejection. A peak 24 hour excretion of HCG in the second month of human pregnancy may reach 800,000 I.U.
and
Mean sx Standard
a 6
Assuming a 50 kilogram woman, the equi\,alent dose in a 15 gram mouse would be 250 I.U. This dose injected intraperitoneally caused agitation, the mice ran wildly around their cages and their fur stood on end. A 200 I.U. injection was tolerated without event. The grafts were inspected daily from the seventh day onward. Falling off of the black scale of the graft dermis was taken as the end point of survival. Results
As Table I indicates, there was a somewhat longer average survival of skin grafts in those mice treated with HCG-13.3 days as opposed to 11.3 days in controls. The standard error of the difference of the means is 0.475, or a relative deviate of 4.21. These survivals are significantly different at the P less than 0.001 level. Statistical analysis hy the t test confirms the same le\fel of significance. Comment
This experiment supports the concept that the specific hormonal changes of pregnancy are associated with the observed lowering of maternal immunologic reactivity. Continued studies in this area will be of value in defining the pregnancy homograft problem, and likel) of value in immunosuppression associated with homotransplantation.
574
Pearse
and
Kaiman
REFERENCES
1.
Billingham, R. E.: New England J. Med. 270: 667, 720; 1964. 2. Lanman, J. T.: J. Pediat. 66: 525, 1965. 3. Kirby, D. R. S., Billington, W. D., Bradbury, S., and Goldstein, D. J.: Nature 204: 548, 1964. 4. Simmons. R. L., Cruise, Virginia, and McKay, D. G.: AM. J. OBST. & GYNEC. 97: 218, 1967.
5. 6.
Nelson, J. H., et al.: Obst. 1966. Serr, D. M., Biran, S., Harefuah 67: 152, 1964. 42nd d Dewey Streets Omaha, Nebraska 68105
& Gynec. and
27: 591
Neuman,
Z
Human chorionic gonadotropin skin homograft WARREN
H.
HAROLD
KAIMAN,
Omaha,
and
surv’ wal
PEARSE,
B.S.. B.S.,
M.D. M.D.
Nebraska
Rejection of Jkin homografts days to an average of 13.3 human chorionic gonadotropin. a homograft is discussed.
in immature mice war delayed days by the daily intraperitoneal Possible relationship to the
?'H E R E AS 0 N s for the in utero survival of mammalian pregnancy, a homograft, are of key importance in the understanding of reproductive physiology, as well as the entire tissue transplantation problem. Excellent reviews of the subject include those of Billingham1 and Lanman.” Of the four protective mechanisms usually suggested as responsible for pregnancy survival, natural and animal experimentation has shown that nonantigenicity of the fetus and the uterus as a privileged transplantation site are not valid reasons. Both the trophoblastic “barrier” and lowered reactivity during maternal immunologic pregnancy are related to fetal homograft survival, but neither offers the entire explanation, and the modes of action of both are not completely clear. From the Department Gynecology, Uniuersity College of Medicine. Supported in Public Health ROI-AMA-l-09288 2TI-HD-18.
Part by Service
of Obstetrics of Nebraska United
Grant
and
A “iibrinoid” barrier around individual trophoblastic cells has been suggested as responsible for their nonantigenicity,3 but recent electron microscopic studies have not demonstrated this layer.+ Nelson and associates5 described the effects of HCG and HCG plus estrogen on the thymolymphatic system in rats. With HCG in doses extrapolated from human pregnant levels there was a significant weight reduction in the thymus, but no weight changes in the spleen, lymph nodes, or intestinal lymphoid masses. With HCG plus estrogen, acute atrophy of the thymus occurred. Serr. Hiran, and Neumanc studied the effects of cortisone. estrogen, HCG, progesterone, a combination of estrogen, progesterone, and HCG, and normal pregnancy on the survi\,ai of full thickness skin homografts in mice. There was a progressively increased survival of the grafts compared to controls in the order listed, with the longest survival (a time increase of 87 per cent’) occurring in pregnancy. Because HCG is unique to the pregnant
and
States
Training
from an average of 11.3 injection of 200 I.U. of problem of pregnancy as
Grant
572
Volume Number
98 4
HCG
state; the dosage of HCG used relatively lo\~-50 I.U. in 30 and pregnancy itself produced homograft survival than the hormones, we elected to begin pression studies with HCG. Materials
and
by Serr was gram mice; a longer use of any immunosup-
Table I. Number Day
8 9 10 II
skin
homograft
of new
survival
573
rejects
Cor1trol
1 9
/
With HCG 2 1 1 5 4 8 9
13 14 15 16
7 3 IO 1 5 2 1
Total
:19
44
13.3 days 2.23 error cf difference
11.3 days 2.09 0.475
12
methods
Ninety immature female mice of the congenic resistant strain B,, D, and 5 female mice of the inbred partner strain C57BL/lO SC Sn (H-2 in compatability) were obtained from the Jackson Memorial Bar Harbor. They weighed Laboratories, approximately 15 grams each. The technique of grafting was as follows: 1. Depilate mice from scapula to tail with Nair one or 2 days before grafting. 2. Kill donor mouse (C57BL/lO SC Sn). 3. Remove tail skin of donor by circular incision with a No. 21 Bard-Parker blade, pulling skin toward caudal end. 4. Place tail skin in Petri dish with filter paper bottom, and float in sterile saline. 5. Wash blood from tail skin. 6. Cut skin to appropriate size (about 3 ‘9: 4 mm.) . 7. Anesthetize depilated mouse, and secure on animal board. 8. Swab depilated area with 70 per cent alcohol. 9. With forceps, pinch skin in middle of back and raise. With a No. 15 Bard-Parker blade remove a 3 x 4 mm. area of raised skin down to panniculus carnosus. 10. Place donor skin rapidly on dry filter paper and then on graft recipient area. 11. Dust graft area with Neosporin Powder and tape with Elastiderm tape. Mice were randomly removed from their cages and numbered by marked tape. Odd numbered mice were grafted only. Even numbered mice were grafted and received 200 I.U. of HCG intraperitoneally daily, beginning on the day of the graft, and continuing until rejection. A peak 24 hour excretion of HCG in the second month of human pregnancy may reach 800,000 I.U.
and
Mean sx Standard
a 6
Assuming a 50 kilogram woman, the equi\,alent dose in a 15 gram mouse would be 250 I.U. This dose injected intraperitoneally caused agitation, the mice ran wildly around their cages and their fur stood on end. A 200 I.U. injection was tolerated without event. The grafts were inspected daily from the seventh day onward. Falling off of the black scale of the graft dermis was taken as the end point of survival. Results
As Table I indicates, there was a somewhat longer average survival of skin grafts in those mice treated with HCG-13.3 days as opposed to 11.3 days in controls. The standard error of the difference of the means is 0.475, or a relative deviate of 4.21. These survivals are significantly different at the P less than 0.001 level. Statistical analysis hy the t test confirms the same le\fel of significance. Comment
This experiment supports the concept that the specific hormonal changes of pregnancy are associated with the observed lowering of maternal immunologic reactivity. Continued studies in this area will be of value in defining the pregnancy homograft problem, and likel) of value in immunosuppression associated with homotransplantation.
574
Pearse
and
Kaiman
REFERENCES
1.
Billingham, R. E.: New England J. Med. 270: 667, 720; 1964. 2. Lanman, J. T.: J. Pediat. 66: 525, 1965. 3. Kirby, D. R. S., Billington, W. D., Bradbury, S., and Goldstein, D. J.: Nature 204: 548, 1964. 4. Simmons. R. L., Cruise, Virginia, and McKay, D. G.: AM. J. OBST. & GYNEC. 97: 218, 1967.
5. 6.
Nelson, J. H., et al.: Obst. 1966. Serr, D. M., Biran, S., Harefuah 67: 152, 1964. 42nd d Dewey Streets Omaha, Nebraska 68105
& Gynec. and
27: 591
Neuman,
Z