Appearance and Persistence in Rabbits' Blood of Rabicidal Antibodies Produced by Various Methods of Anti-Rabies Immunisation

Extract

A. Results following the subcutaneous inoculation of 1400 grm. rabbits with a 2 per cent. suspension of living fixed virus in a dosage of 5 c.c. daily on 14 consecutive days (1·4 grm.):

(1) Fresh living fixed virus introduced into rabbits subcutaneously produces in the sera of these animals so high a degree of rabicidal power that one unit volume of undiluted serum is capable of neutralising, when antibody formation is at a maximum, 16 unit volumes of a 1:100 suspension of freshfixed virus in n.s.s.

(2) Rabicidal properties in the serum are demonstrable 18 days after the commencement of treatment, one unit volume of serum then neutralising one volume of a 1:100 f.v. suspension in n.s.s.

(3) Rabicidal antibody content reaches a maximum between 50 and 60 days after completion of treatment, and thereafter diminishes somewhat gradually.

(4) Immune sera retain their rabicidal properties for a period extending over 222 days, viz. from the 4th to the 226th day after completion of treatment.

B. Results following the subcutaneous inoculation of 1400 grm. rabbits with a 2 per cent. suspension of killed carbolised-fixed virus in a dosage of 5 c.c. daily on 14 consecutive days (1·4 grm.):

(1) Killed carbolised virus administered to rabbits subcutaneously produces a very considerable degree of rabicidal power. The maximum reached, however, falls much short of that attained by immunisation with fresh-fixed virus and is only one-third of that following the use of etherised vaccine, one unit volume of serum neutralising 8 unit volumes of a 1:100 f.v. suspension in n.s.s.

(2) Rabicidal properties in the serum are demonstrable 18 days after the commencement of treatment, one unit volume of serum neutralising one unit volume of a 1:100 f.v. suspension in n.s.s.

(3) Rabicidal antibody content reaches a maximum some 50–60 days after completion of treatment, and thereafter subsides fairly rapidly.

(4) Sera of rabbits immunised with carbolised-fixed virus retain their rabicidal properties for a period of 131 days, viz. from the 4th to the 135th day after completion of treatment.

C. Results following the subcutaneous inoculation of 1400 grm. rabbits with a 2 per cent. suspension of killed etherised virus in a dosage of 5 c.c. daily on 14 consecutive days (1·4 grm.):

(1) Killed etherised virus introduced into rabbits subcutaneously produces in these animals' sera such an extraordinary degree of rabicidal power that, when antibody formation has reached a maximum, one unit volume of undiluted serum is capable of neutralising as many as 24 volumes of a 1:100 f.v. suspension in n.s.s.

(2) Rabicidal properties in the serum are demonstrable on the last day of treatment (14 days after commencement), one unit volume of serum neutralising one unit volume of a 1:100 f.v. suspension in n.s.s.

(3) Rabicidal antibody content reaches a maximum between 50 and 60 days after completion of treatment, and thereafter diminishes fairly gradually.

(4) Sera of rabbits immunised with etherised-fixed virus retain their rabicidal properties for a period of 226 days, viz. from the 14th to the 240th day after commencement of treatment.