ON THE IMMUNOLOGIC RELATIONSHIP BETWEEN GRASS

POLLEN AN11 SEED”

IIAIJRENCE: ~‘ARMER, M.1). NEW YORK C(ITY

I T IS a well-known phenomenon that individuals suffering from grass pollen hay fever are allergic to many different grass pollens. It was

even shown that grass hay fever subjects who had never been in contact with Bermuda grass1 or Chactuws fasciculatus, an exotic species,* gave positive reactions to these grasses. Furthermore, it is frequently pos- sible to desensitize a grass hay fever patient showing multiple hyper- sensitivity by using a single grass pollen extract (Coca). This presumably could not be ach.ieved if the grass pollen allergens were strictly specific.

Although these observations show that there is no strict specificitS among the pollens of the various grasses, this lack of specificity does not t,ransgress the line of the family. Pet,ow and I3 had the opportunity of testing a large number of Europeans suffering from grass hay fever. Although all of these patients gave positive skin reactions to the grass pollens, not one of them reacted to ragweed pollen with which they had had no contact.

In earlier work on the chemical nature of pollen allcrgens,4 I fre- quently found that guinea pigs which were sensitized to a certain grass pollen extract, would react nonspecifically to another grass pollen ex- tract. However, the animals only rarely reacted to unrelated allergens; e.g., feather extracts.

These observations suggest that although the various grass pollen allergens are not strictly specific, they are, nevertheless, closely related to one another.

Since Wells and Osborne5 have shown that there is an immunologic relationship between the antigens of various plant seeds, t,he question arose whether there is a relationship between the antigens of the pollens and seeds of the same plant. The botanist Mez believes that “all living cells of the same plant show a similarity of their reactions.”

In sensitization experiments on guinea pigs,” I have shown that there is no relationship between the pollen and seed antigens of Dactylis glomeratn. Skin t,ests upon individuals suffering from hay fever demon- st,rated that there is no relationship between the pollen and seed antigens of Dnctylis glomuratn, phleunz p,ratense and Alopecurus.

Skin tests and sensitization experiments with rye seed extracts sug- gested that, these ext,rachs contain irritating substances which can cause nonspecific reactions.

*From the Laboratories of F’athology :md the Second Medical (Cornell) Division of Bellevue Hospital.

Aided by a grant from the Department of Medicine of Cornell University Medical College.

FARMER : GRASS POLLEN AND SEED 339

I therefore repeated the work with rye pollen and rye seed extracts on a group of patients, and enlarged the number of grasses by testing with pollen and seed extracts of timothy and orchard grass.

The extracts were prepared by first treating the pollens or ground seeds for fifteen minutes with ether. The ether was decanted, and the pollens or seeds were then extracted with I per cent sodium chloride solution (containing 0.3 per cent phenol) -first in a shaking machine for one hour, and then overnight in the ice box. The extraction fluid was filtered first through paper and then through a Bcrkefeld filter. The extracts were finally tested for sterility.

The nitrogen content of the pollen extracts ranged from 0.12 to 0.23 mg. per cc., of the seed extracts from 0.19 to 0.43 mg. per cc.

The extracts were applied to skin abrasions made on the patient’s fore- arms with a Pirquet borer.

The experiments were carried out on 12 patients who, at some previous time, had shown positive skin reactions to timothy pollen extracts. Seven of these patients were refractive to all of the extracts used, 5 gave

I TIMOTHY I ORCHARD GRASS

PATIENT POLLEN SEED POLLEN SEED

0. D. $ t4-tt 0 t+t 0 T.K. 0 tt 0 ttt 0 A.G. 9 it 0 + t 0 B. E. 0 tttt 0 tt 0 S. H. Q tttt 0 t-t- 0

RYE

PorlLEs (SPRING) (WINTER) SEED SEED

ttt 0 0 + n 0 0 0 0 t 0 0 0 0 0

the results shown in Table I. These patients showed marked reactions to the pollens of timothy, orchard grass, and rye, but were not sensitive to the corresponding seeds.

Although a close immunologic relationship between the pollens of dif- ferent grasses may be assumed, it has been shown in the foregoing and in earlier experiments that there is no immunologic relationship between the pollens and seeds of the same plant, in spite of their close biological relationship.

REFERENCES

1. Chobot, R.: Studies in Specific Hypersensitiveness; Relationship of Atopens in Pollen of Bermuda Grass (Cynodon Dactyton) and Timothy Grass (Phleum Pratense), J. Immunol. 16: 281, 1929.

2. Coca, A. F., Waker, M., and Thommen, A. A.: Asthma and Hay Fever in Theory and Practice, 1931, Springfield, C. C. Thomas.

3. Petow, H., and Farmer-Loeb, L.: Erfahrungen iiber die desensibilisierende Be- handlung des Heufiebers, Klin. Wchnschr. 6: 57, 1927.

4. Farmer-Loeb. L.: Untersuchuneen iiber die chemische Natur der Alleroene. Biochem.’ Ztschr. 220: 1$?30. 0 / 432,

5. Wells, and Osborne: J. Infect. Dis. 12: 341, 1913. 6. Farmer-Loeb, L.: Biochem. Ztschr. 203: 226, 1928.