In 1927 the foundation stock for this experiment was picked at random from the guinea pig colony of the Genetics Department at Iowa State College. Since then three generations of individuals, selected both for resistance and susceptibility to protein reaction, have been obtained

Shrigley, E. W.

English

University of Northern Iowa

Proceedings of the Iowa Academy of Science Volume 38 Annual Issue Article 97 1931 Studies in the Selection for Susceptibility and Resistance to Anaphylactic Shock in Guinea Pigs E. W. Shrigley Iowa State College Copyright ©1931 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Shrigley, E. W. (1931) "Studies in the Selection for Susceptibility and Resistance to Anaphylactic Shock in Guinea Pigs," Proceedings of the Iowa Academy of Science, 38(1), 249-253. Available at: https://scholarworks.uni.edu/pias/vol38/iss1/97 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. STUDIES IN THE SELECTION FOR SUSCEPTIBILITY AND RESISTANCE TO ANAPHYLACTIC SHOCK IN GUINEA PIGS E. w. SHRIGLEY MATERIAL AND TECHNIQUE In 1927 the foundation stock for this experiment was picked at random from the guinea pig colony of the Genetics Department at Iowa State College. Since then three generations of individuals, selected both for resistance and susceptibility to protein reaction, have been obtained. Each animal received a sensitizing dose of 0.1 cc. of normal horse serum thirty days after birth. At the age of sixty days a second injection of 6 cc. of normal horse serum was administered, both injections being intraperitoneal. In this manner there was produced a typical anaphylactic shock such as described by Zinsser ( 1923) and others. The intensity of the individual's reaction to this foreign protein was measured mostly by its minimum rectal temperature after the administration of the shock dose. Temper-atures were taken thirty minutes before the shock dose, at the time of the shock dose, and at thirty minute intervals for three hours after its administration. From the data thus obtained, indi-viduals surviving and having minimum rectal temperatures of 97°F. and above after the shock, and coming from matings having like records, were kept for the perpetuation of the resistant strain. The animals surviving and having minimum rectal temperatures of 94°F. and below, after the shock, and coming from low matings, that is where both parents have shown low temperatures, were reserved for the susceptible strain. Individuals falling between 94°F. and 97°F. were discarded. Due to the fact that the exact temperatures resulting from the shock were difficult to determine because of so many variables, only animals in the two extremes of these high and low categories were kept for breeding purposes. The rectal temperature was taken as typifying the intensity of the individual's reaction for, according to Zinsser ( 1923, page 433), "The fall of temperature first described by H. Pfeiffer, however, seems to be an occurrence which, though standing in no causative relation to the symptoms as a whole, is so constant and 249 1Shrigley: Studies in the Selection for Susceptibility and Resistance to AnaPublished by UNI ScholarWorks, 1931250 IOWA ACADEMY OF SCIENCE [VoL.XXXVIII well marked that it has been taken by a number of workers as one of the necessary criteria for the characterization of the anaphylactic condition." This agrees with the observations in this experiment. The individual that runs a low temperature shows very definitely other conditions which are characteristic of severe anaphylactic shock. RESUL'l'S In the control stock (Table I), consisting of 163 animals having no known hereditary background of anaphylaxis, individuals hav-ing minimum te~peratures of 97°F. and above included 15.3 per cent of the total tested population. Those between 94°F. and 97°F. included 24.0 per cent of the total tested population, while 31.3 per cent of the individuals had temperatures of 94°F. and below. The mortality percentage in the control stock was 29.4 per cent. The minimum temperature of those dying was not re-corded because of the natural drop occurring at death. The resistant strain (Table I), including 143 individuals from three selected generations, shows that 36.3 per cent of all animals tested had minimum temperatures of 97°F. and above, an increase of over 100 per cent above the control animals. Thir-teen and nine-tenths per cent of the individuals went between 94°F. and 97°F., and 25.9 per cent were 94°F. and below. The mortality of the group went down to 23.9 per cent, a drop of 5.5 per cent from the controls. The minimum temperatures of those dying were disregarded. These percentages are determined on the / resistant population as a whole starting with the first selected generation. Table I -Percentages of those individu.als having minimum rectal temper-atures of 97° F. and above, between 97° F. and 94° F., an& 94° F. and below in the control stock, resistant strain, and susceptible strain. Percent-ages are based on total number of animals ·tested in each group No. oF TEMPERATURES STOCK lNDTVID- 97° F. 97° F. 94° F. MoR-UALS AND TO AND TALITY ABOVE 94° F. BEr,ow Control 163 15.3 24.0 31.3 29.4 Resistant Strain 143 36.3 13.9 25.9 23.9 Susceptible Strain 116 27.6 12.9 17.2 42.3 In the susceptible line (Table I), having a total of 116 animals from three generations, the high class included 27 .6 per cent of the individuals tested, the medium, namely between 94°F. and 97°F., 12.9 per cent, and the low class, 94°F. and below, only 17.2 per cent of the total number of animals tested. While selection in 2Proceedings of the Iowa Academy of Science, Vol. 38 [1931], No. 1, Art. 97https://scholarworks.uni.edu/pias/vol38/iss1/971931] ANAPHYLACTIC SHOCK IN GUINEA PIGS 251 the susceptible strain has not produced significant percentage differ-ences between the high and low temperature classes, still the mor-tality percentage increased 12.9 per cent, this being 42.3 per cent of the total susceptible individuals tested. While the percentage differences between the control stock and the two selected strains are in some cases not statistically signifi-cant, there is an increased per cent of individuals over the control group having minimum rectal temperatures of 97°F. and above in the resistant strain. Also, in the susceptible strain there is an increase of mortality above the control stock. The differences in mortality between resistant and susceptible lines is still greater. Further generations will tell whether these differences are biologi- ' cally significant. This being the case, assuming that there is a significant change, it would appear at present that mortality is a better indication of susceptibility than temperature, although the criterion for selection in the low line has been mainly minimum rectal temperature. This basis of selection in the susceptible strain may account for the high percentage of individuals having tem-peratures of 97°F. and above in this group. The mere fact that an animal survives the shock dose of serum shows that it has some ability to resist the shock. Naturally, then, some of the progeny from the survivors in the susceptible line will give a high tem-perature when tested, while a large majority of the would-be-low-reactors, die. This leaves the percentage of low temperatures small in the susceptible line. In view of these facts, the breeding pro-gram has been changed in the susceptible line to a progeny test scheme in which animals are allowed to reproduce before they are tested. In this plan selection will be made from mortality as well as temperature records. By generations the results become more variable. In the resistant line there is a trend upward of the minimum temperature from 97°F. and above as represented in fig. I. The temperatures, from 94°F. and below, and mortality show a slight general decline. In the susceptible strain, treatment from the standpoint of generations emphasizes the inconsistencies within this line. The conclusion is, as stated in an earlier part of this paper, that the same type of breeding program will not work for both selected lines. In the susceptible line it is apparently necessary to take into account another factor other than minimum temperature, prob-ably mortality. Figure II shows that the survivors of the 8 1 generation carried the potentialities of high and low temperatures rather than a high 3Shrigley: Studies in the Selection for Susceptibility and Resistance to AnaPublished by UNI ScholarWorks, 1931252 IOWA ACADEMY OF SCIENCE 'Pev '•"'~ of x ... 1v••~•'• T.u"&" .so "0 . ,, .. 10. I 0, /. ""· /" ' ' \ \ I ' I \/ Co"~'l'ol •• I I [VoL. XXXVIII .. T•""'r&"'~1i:: .... v .. ",.~ ..... •"·"~ 'l•j. " l.&lo.., - - - .. M ., \' •\ &t'\ Fig. 1. The trend of temperatures, 970F. and above, 94°F. and below, and mor-tality in the resistant strain. Pa-t C:&'ftt' ., r ............... 1. lutcL '·· ro. .a o. &o. /0 0 I\' ,' \ I \ I ' / \ I \ I t. '· \ Ge .. C'Y4t'io"~ <"••'"01 .&, ~. ,.~ Lt,e'-• \ -s Tcrn~c.ta.t' .. n .. .,;. .......... -----s Mo'f't,.lit't ,.,;, .. ••••w Fig. 2. The trend of temperatures 97°F. and above, 940F. and below, and mor-tality in the susceptible strain. 4Proceedings of the Iowa Academy of Science, Vol. 38 [1931], No. 1, Art. 97https://scholarworks.uni.edu/pias/vol38/iss1/971931] ANAPHYLACTIC SHOCK IN GUINEA PIGS 253 percentage of mortality. These survivors in the S1 when mated gave to their offspring in the S2 generation still more ability to resist the shock. In the Sa. generation this quality of resistance is accentuated even more, for the mortality percentage is below that of the other two classes. This substantiates the statement men-tioned before, namely, the fact that animals survive is evidence that they have the ~bility to resist the shock dose. Therefore, some of their progeny also carry this resistance. CONCLUSION It may be possible by selection to establish two strains of guinea pigs, one resistant, the other susceptible to anaphylactic shock. However, the same technique of selection cannot be effec-tively used for both the resistant and susceptible strains. The author wishes to thank Professor vV. V. Lambert, for his many helpful suggestions. LITERATURE CITED ZINSSER, HANS. 1923. Infection and resistance. Macmillan Co., New York. IowA STATE CoLLEGE, AMES, IowA. 5Shrigley: Studies in the Selection for Susceptibility and Resistance to AnaPublished by UNI ScholarWorks, 1931

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