[Code of Federal Regulations]
[Title 9, Volume 1]
[Revised as of January 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 9CFR113.46]

[Page 607]
 
                  TITLE 9--ANIMALS AND ANIMAL PRODUCTS
 
  CHAPTER I--ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF 
                               AGRICULTURE
 
PART 113--STANDARD REQUIREMENTS--Table of Contents
 
Sec. 113.46  Detection of cytopathogenic and/or hemadsorbing agents.

    The tests for detection of cytopathogenic and/or hemadsorbing agents 
provided in this section shall be conducted when prescribed in an 
applicable Standard Requirement or in the filed Outline of Production 
for a product.
    (a) Test for cytopathogenic agents. One or more monolayers that are 
at least 6 cm\2\ and at least 7 days from the last subculture shall be 
tested as provided in this paragraph.
    (1) Stain each monolayer with a suitable cytological stain.
    (2) Examine the entire area of each stained monolayer for evidence 
of inclusion bodies, abnormal number of giant cells, or other 
cytopathology indicative of cell abnormalities attributable to an 
extraneous agent.
    (b) Test for hemadsorbing agents. One or more monolayers that are at 
least 6 cm\2\ and at least 7 days from the last subculture shall be 
tested as provided in this paragraph.
    (1) Wash the monolayer with several changes of phosphate buffered 
saline.
    (2) Add an appropriate volume of a 0.2 percent red blood cell 
suspension to uniformly cover the surface of the monolayer of cultured 
cells. Suspensions of washed guinea pig and chicken red blood cells 
shall be used. These suspensions may be mixed before addition to the 
monolayer or they may be added separately to individual monolayers.
    (3) Incubate the monolayer at 4 deg. C for 30 minutes, wash with 
phosphate buffered saline, and examine for hemadsorption.
    (4) If no hemadsorption is apparent, repeat step (b)(2) of this 
section and incubate the monolayers at 20-25  deg.C for 30 minutes, wash 
with phosphate buffered saline, and examine again for hemadsorption. If 
desired, separate monolayers may be used for each incubation 
temperature.
    (c) If specific cytopathology or hemadsorption attributable to an 
extraneous agent is found, the material under test is unsatisfactory and 
shall not be used to prepare biological products. If an extraneous agent 
is suspected because of cytopathology or hemadsorption and cannot be 
eliminated as a possibility by additional testing, the material under 
test is unsatisfactory.

[50 FR 441, Jan. 4, 1985, as amended at 58 FR 50252, Sept. 27, 1993]