Physiological Response of the Cunner, Tautogolabrus adspersus, 
to Cadmium. 
IV. Effects on the Immune System 
RICHARD A. ROBOHM and MAUREEN F. NITKOWSKI'! 
ABSTRACT 
Two elements of the immune system in cunners, Tautogolabrus adspersus, were examined 
after 96-hr exposure to cadmium: 1) clearance of intracardially injected bacteria from the 
bloodstream and 2) ability to produce antibody against intraperitoneally injected sheep red 
blood cells (SRBC). Exposure to 12 ppm cadmium increased the rates of bacterial uptake in 
phagocytes of the liver and spleen but significantly decreased the rates of bacterial killing 
within these cells. Exposure of fish at 3 to 24 ppm cadmium failed to influence antibody produc- 
tion against SRBC. These results indicate that cadmium affects one aspect of cellular immunity 
but not humoral immunity in cunners. This effect may increase susceptibility to infection. 
INTRODUCTION 
There is evidence that cadmium poisoning in 
teleosts disrupts respiratory processes (Schweiger, 
1957; Mount and Stephan, 1967) and damages 
kidneys (Gardner and Yevich, 1970) and gills (Mount 
and Stephan, 1967; Gardner and Yevich, 1970). The 
exact mechanisms of these effects are unknown, 
although some evidence in liver, kidney, and other 
tissues of mammals (Simon, Potts, and Gerard, 1947) 
and fish (Jackim, Hamlin, and Sonis, 1970) indicates 
that enzyme systems are inhibited. If there is inhibi- 
tion in rapidly growing or metabolizing cells, then 
cells of the immune system in fish may also be 
affected. Identification of such effects, in addition to 
being useful as indicators of toxicity, may, in part, ex- 
plain environmental mortalities of fish. For example, 
if a pollutant can inhibit production of antibody by 
the lymphocytes or in some way reduce the effec- 
tiveness of reticuloendothelial system phagocytes, fish 
may become susceptible to infection. A report by Pip- 
py and Hare (1969) linking bacterial infection of 
salmon with sudden spikes of copper and zinc levels in 
a Canadian river is indicative that metal pollution 
may indeed lower fish immunity. 
The following investigation was undertaken to 
determine whether short-term exposure of the cunner 
to sublethal cadmium levels would limit antibody 
production or reduce clearance of bacteria from the 
blood, spleen, and liver. 
Reprinted from NOAA Technical Report NMFS SSRF-681 
METHODS AND MATERIALS 
Fish Holding and Cadmium Exposure 
Cunners, Tautogolabrus adspersus, were captured 
from the wild, acclimated to artificial seawater, and 
exposed to 3 to 48 ppm Cd*+ (as CdCl,°2'2 H,O), as 
described by Calabrese, Collier, and Miller (this 
report, Part I). Some fish were immunized (as 
described below) with sheep red blood cells (SRBC), 
removed from Cd?+ treated water, and held an ad- 
ditional 10 days at ambient temperature (23 + 2°C). 
In two experiments these immunized fish were held in 
20-gal fiber glass aquaria containing recirculating 
seawater under constant charcoal filtration. The fish 
(with dorsal spine, pectoral fin, or pelvic fin clipped to 
denote levels of cadmium treatment) were held nine 
or less per tank, and the water changed every second 
day. In two later experiments with immunized fish, 
fins were no longer clipped, and fish were held in run- 
ning seawater (20°-23°C) in 500-gal fiber glass tanks 
partitioned off with polyethylene mesh. 
Some fish were exposed to 12 ppm Cd** treated 
water then removed and held for 1 or 2 days in the 
running seawater system. These fish were challenged 
by intracardial injection of bacteria, as described 
below. 
Immunization and Collection of Antisera 
Sheep red blood cells in Alsever’s solution were 
washed in phosphate buffered physiological saline 
(PBS), pH 7.2, until the supernatant was free of 
hemoglobin and then diluted in PBS to 0.5% suspen- 
sion (packed cell volume/volume PBS). Fish were 
weighed and injected intraperitoneally with 0.2 m! of 
the suspension per 40-g fish (i.e., 2.6 X 10° ml packed 
SRBC/g fish weight). SRBC injections were made at 0 
