CA1171357A

CA1171357A - Vaccine against pertussis

Info

Publication number: CA1171357A
Application number: CA000383385A
Authority: CA
Inventors: Hrisso K. Vesselinova-Jenkins
Original assignee: Pharmachim DSO
Current assignee: Pharmachim DSO
Priority date: 1981-08-07
Filing date: 1981-08-07
Publication date: 1984-07-24

Abstract

7.
VACCINE AGAINST PERTUSSIS
ABSTRACT
A vaccine effective against pertussis in infants and which is preferably orally administered comprises live pertussis bacteria of the Bordetella strain EM 1964.

Description

~L171357.

VACCINE AGAINST PERTUSSIS
This invention relates to an orally administrable vaccine against pertussis.
One vaccine which has hitherto found general use in the protection of babies against contracting pertussis (whooping cough) comprises killed Bordetella pertussis bacteria, generally in the form of a suspension in a suitable diluent such as isotonic sodium chloride solution. The use of such a vaccine has certain disadvantages. In particular it causes several allergic reactions, as well as complica-tions affecting the central nervous system, such as convul-sions and encephalopathies (see Kulenkampff M., Schwartzman J.S. and Wilson J. aNeurological complications of pertussis inoculation~>, Archives of Disease in Childhood), 49, 46-49 (1974)-According to the present invention, there is provided a pertussis vaccine which comprises live pertussis bacteria of the Bordetella strain EM 1964 in association with a pharmacologically acceptable carrier.
The vaccine of the present invention has been found to be free from the aforementioned side efects char-acteristic of the use of dead Bordetella pertussis bacteria.
Moreover, a vaccine according to this invention possesses high immunogenicity after Kendrick and minimal toxicity.
The bacterial strain used in the vaccine of the present invention was first isolated from the urine of a child ill with pertussis and was registered in the State Institute for Drug Control, Boulevard V. Zaimov 26, Sofia, Bulgaria under No. 321 from which it has been freely avail-able since 26th December, 1968. The strain has been subse-quently characterised as a result of work carried out by the Public Health Laboratorles, Cardiff, Wales and the Department of Microbiology, Universit~ of Manchester.
The vaccine of the present invention differs from ~1713~7 those hitherto used in the treatment of pertussis in that it contains live bacteria. A suitable vaccine will be one containing from 3 million to 3 milliard microbe organisms in 1 ml. diluent which will usually be physiological saline.
The vaccine will usually be administered in two portions at a ten day interval using e~ual doses of 1.5 million to 1.5 milliard microbe organisms per administration.
The pertussis vaccine of the present invention is obtainable by cultivating Bordetella pertussis strain EM 1964 on Borget-Genou medium for 48 hours at 37C. The suspension whlch is obtained may be taken up in physiological saline solution and diluted in amounts such as shown in Tables 1 and 2 which follow. Standardisation of the vaccine is in accordance with international standards. The vaccine is to lS be given orally.
Table l shows the effect of the vaccine on mice infected with virulent pertussis bacteria. This Table shows that mice administered with the live vaccine of this inven-tion administered orally did not suffer lethal conse~uences of the infection. In contrast 100% of the non-immunized mice died.

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Table 1 Testing of immunogenicity on mice after Kendrick Method Group Dose of No. Intracerebral of of Vaccine of inoculation with immunisation Mice (No. o~ mice 10ODL50 of No. microbe in Bordetella organisms) group Pertussis 18323 died % of . survival 1 3 milliard 10 2 80%
. Intraperito- 2300 million 17 1 94.12%
neal 3 30 '~ 11 _ 100%

4 3 " 16 7 56.35%
control 9 9 0~
_ , 1 3 milliard 18 2 89.89%
2 300 million 14 2 85.71%
Oral 3 30 million 17 2 88.24%
4 3 " 12 _ 100%
control 8 8 0%

q'he Table shows that those white mice immunized orally with doses of from 3 million to 3 milliard microbe organisms depending upon the group of mice concerned, showed 85.71 to 100% survival after intracerebral inoculation with LD50 of the highly virulent strain of Bordetella pertussis 18323. At the same time all the non-immunized control mice died.
The results were even better when the vaccine of this invention was employed with a second series of mice ~:~7:~357 immunized parenterally by intraperitoneal injection. The same range of dosages was employed in respect of groups although the group sizes Were different. The results ob-tained were almost as good as With oral administration which nevertheless is obviously a preferable method with infants. The percentage ~survival here ranged from 56.3 to 100%.
In subsequent tests, the toxicity of the live pertussis vaccine of this invention was tested on white mice.
The results obtained are set out in Table 2.
Table 2 _ Method of Group No. of Immunization Total ~ of immunization of microbe toxicitymortality Mice organisms after(lst + 2nd) No. per dose _ of vaccine 1st 2nd . dose dose Intraperit- 1 1.5 mil~iard 2/164/14 37.5 . oneal 2 150 million 0/192/19 10.5 3 15 " 0/11 0/11 0 4 1.5 " 2/18 0/1611.1 control1/10 0/9 10 __ Oral 1 1.5 milliard 0/180/18 0 2 150 million 0/140/14 0 3 15 " 1/20 2/19 15 .
4 1.5 " 0/13 1/13 7 control1/10 0/9 10 _ The fractions in the columns denoting immunization toxicity signify the number of immunized mice as the ~enomi-3 5 ~

nator and the number of dead mice as the numerator.
It can be seen from Table 2 that the toxic effectof the vaccine depends on the dose employed, the number of doses and the method of application. In particular the results show that the vaccine leads to much higher percent-age lethality results with those mice which were immunized intraperitoneally or those inocuIated with a larger dose (3 milliard pertussis bacteria). The mortality of mice immunized twice intraperitoneally or inoculated with a larger average dose (3 milliard pertussis bacteria) was comparatively high. When mice were immunized intraperito-neally twice, the mortality after the second immunization was twice as great as that after the first dose of vaccine.
This increase in mortality is assumed to be due to certain allergic reactions caused by the administration of the second dose of vaccine. In the remaining subgroups of experimental animals, the mortality after the first and second immunizations given orally was minimal. This leads to the conclusion that when the vaccine is administered orally, it does not set up any allergic reactions in the alimentary track. The Table thus indicates that minimum mortality effects are achieved after administration of the live vaccine by oral means. This is therefore the preferred method for administering the vaccine to achieve minimum toxicity.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A pertussis vaccine which comprises live pertussis bacteria of the Bordetella strain EM 1964 in association with a pharmacologically acceptable carrier.

2. A vaccine as claimed in claim 1 in which the carrier is physiologically saline.

3. A vaccine as claimed in claim 1 or 2 which is in dosage unit form, each dosage unit containing from 3 million to 3 milliard microbe organisms per 1 ml.