Markham and Cox appeal from the decision of the Board of Appeals affirming the examiner’s rejection of claims 8, 14, 15 and 16 of their patent application1 which relates to a process of preparing a *359live virus vaccine for various fowl diseases, particularly Newcastle disease, a virus disease of chickens.
Claim 14 reads:
“14. A method of preparing a live-virus fowl vaccine, said vaccine being free of the microorganism causing chronic respiratory disease of fowl, which comprises the step of preparing an aqueous suspension of chick embryo tissue in which live virus is present, adding thereto at least 50 gammas per milliliter of a tetracycline antibiotic and incubating the aqueous suspension for a period of from about 6 hours to 14 days with a temperature ranging from about 0° C. to 50° C. until virus-like microorganisms causing chronic respiratory disease in fowls have been inactivated.”
Appellants state that the standard procedure for preparing live virus vaccine is to inject the virus into the fertile egg and then incubate the egg for a period of time. The chick embryo so formed is ground and the solution of the vaccine is separated from most or all of the ground tissue. The resulting vaccine is referred to as “harvested vaccine.”
The point of novelty of the process claimed here is said to reside in the introduction of a tetracycline antibiotic in specified amounts to the harvested vaccine, followed by a short incubation period. The function of the antibiotic is to destroy Pleuropneumonia-Like-Organisms (hereinafter PPLO) which cause a fowl chronic respiratory disease known as “roup.” It appears that PPLO can be transmitted by the hen to her eggs. If the eggs of a hen having PPLO are used in the preparation of a virus vaccine the fowls vaccinated will develop that disease. The antibiotic will kill PPLO without destroying the live virus in the vaccine, resulting in selective isolation of the virus.
The claims are rejected as unpatentable over several references. The board, however, reached its decision on
Waksman “Streptomycin,” pp. 561— 579 (1949) publ. Williams and Wilkins Co.
Groupe et al., J. of Bact., May 1949, pp. 515-528.
Gross et al., Poultry Sci., Vol. 32, Mar. 1953 pp. 260-263.
The Waksman reference is concerned with the isolation of viruses from admixtures with bacteria. It discloses the addition of streptomycin to embryonating eggs “in attempts to isolate Newcastle virus from material contaminated with bacteria.” It also refers to the use of streptomycin for the freeing of Newcastle virus contaminated with bacteria from “exudates and tissue suspensions.” The Groupe article discloses that both streptomycin and chlortetracycline kill the agents of infectious sinusitis of turkeys which appellants concede to be similar to PPLO.2
Gross et al. teach the control of chronic respiratory disease of chickens with streptomycin, chlortetracycline, oxytetraeycline and chloramphenicol.
The board held that the claimed process would be obvious from Waksman’s disclosure of the selective recovery of viruses from admixtures with bacteria particularly since the Groupe and Gross references “would suggest the substitution of the tetracyclines for the streptomycin of Waksman.”
The principal issue is whether the substitution of chlortetracycline for streptomycin in Waksman’s process would be obvious to one of ordinary skill in the art.
Appellants attempt to establish that said substitution would not be obvious by an affidavit of one Kiser to the effect that streptomycin develops resistant strains of PPLO, and an affidavit of one Adler showing “that streptomycin-re*360sistant strains of PPLO are also found in domestic birds.”
Appellants ask us to conclude from those affidavits “that streptomycin is capable of producing resistant strains of PPLO whereas the tetracycline antibiotics are not.”
The Adler affidavit says that PPLO is a causative agent of chronic respiratory disease in birds and that streptomycin resistant strains are found in birds. It says nothing whatever about tetracyclines. The Kiser affidavit tabulates the effects of streptomycin and chlortetracycline independently on a PPLO strain of avian origin. Chick embryos in eggs were infected by injection into their yolk sac of a suspension taken from the yolk sac of another embryo which died from a PPLO infection. The embryo was also administered varying quantities of antibiotic. After the infected embryo died the strain of PPLO taken from it was used to inject another embryo containing antibiotic. The PPLO inoculated into the second embryo was referred to by Kiser as the “passage strain.” The “parent strain” had never been exposed to an antibiotic. The passage strain and parent strain were regularly compared to determine their relative effectiveness.
, The affidavit concludes that both “chlortetracycline and streptomycin are effective in combating the Pleuro-Pneumonia-Like Organism;” and that the PPLO strain tested developed a resistance to streptomycin within 10 passages whereas resistance to chlortetracycline was not developed within 15 passages through embryos treated with antibiotic.
The Kiser affidavit thus indicates that chlortetracycline has some superiority over streptomycin for the instant purpose. However, the difference in the results obtained between 10 exposures of a specific PPLO strain to streptomycin treated embryos and 15 exposures of that strain to chlortetracycline treated embryos does not necessarily support the conclusion that PPLO does not develop a resistance to chlortetracycline. The difference disclosed by the Kiser affidavit is merely one of degree in the effectiveness of the two antibiotics. Since the prior art clearly suggests the use of chlortetracycline as an alternative to streptomycin, the “mere fact that the results attained may be unexpectedly good is not controlling.” In re Szumski, 302 F.2d 753, 49 C.C.P.A. 1117.
Appellants further attempt to distinguish their process from that of Waksman on the ground that Waksman injects the antibiotic into the eggs rather than into the harvested vaccine. They point out that an overdose of antibiotic will kill the chick embryos, and “if small amounts of tetracyclines were injected into the eggs they would be so diluted by the embryo tissue that on harvest there would not be the concentration of antibiotic called for by the claims.”
Appellants fail to convince us that it is beyond one of ordinary skill, in view of the teachings in the art, to determine an amount of antibiotic that will eliminate PPLO from the harvested vaccine without being lethal to the embryo. It should be remembered that the object of the claimed method is the preparation of live virus “free of the microorganism causing chronic respiratory disease of fowl,” and if the PPLO are destroyed before harvesting, the same result is accomplished. The use of an antibiotic for selectively killing PPLO in the production of the virus fowl vaccine being old, we think it is no more than an obvious alternative to apply the antibiotic to the harvested vaccine instead of adding it to the embryo earlier in the process.
Appellants’ argument that a reference “must contain a teaching that will meet the claims” is not sound. Waksman alone may not “meet the claims,” and therefore not be an anticipation, but Waksman, in view of Groupe and Gross, suggests what is being claimed.
The period and temperature of incubation are disclosed to depend on the antibiotic employed, and to vary within wide limits. No assertion of criticality is made, nor do we see any.
The decision is affirmed.
Affirmed.
. Serial No. 349,986, filed April 20, 1953.
. Wong et al., Poultry Sci., July 1953, pp. 587-598 was cited by the examiner to show that Groupe et al. and Gross et al. concern PPLO. That point is not challenged by appellants.