During pregnancy, the immune response of cattle has an altered potential to overcome infection than during an open period. Several mechanisms seem to control this immune response, and they are being currently researched

Manak, Rita C.

English

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University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Roman L. Hruska U.S. Meat Animal Research 
Center 
U.S. Department of Agriculture: Agricultural 
Research Service, Lincoln, Nebraska 
1982 
Effect of Pregnancy on Disease Resistance 
Rita C. Manak 
U.S. Meat Animal Research Center 
Follow this and additional works at: https://digitalcommons.unl.edu/hruskareports 
 Part of the Animal Sciences Commons 
Manak, Rita C., "Effect of Pregnancy on Disease Resistance" (1982). Roman L. Hruska U.S. Meat Animal 
Research Center. 9. 
https://digitalcommons.unl.edu/hruskareports/9 
This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research 
Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in 
Roman L. Hruska U.S. Meat Animal Research Center by an authorized administrator of DigitalCommons@University 
of Nebraska - Lincoln. 
RitaC.Manak1
EFFECT OF PREGNANCY ON DISEASE RESISTANCE
Summary
During pregnancy, the immune re-
sponseofcattlehasanalteredpotentialto
overcome infectionthan during an open
period. Several mechanisms seem to
control this immune response, and they
are beingcurrentlyresearched.
Introduction
During pregnancy,the dam's ability
to respondto bacteriaand viruses and to
resist infection (its immune system) is
alteredsomewhatto protectthedevelop-
ingfetus.While thissystemmustcontinue
to protect against infection, it must be
modulatedtoavoidrejectingthefetusas if
itwerea growingforeignorgantransplant.
A disruptionof thisbalancehas impacton
damandfetalhealthas wellas on embryo
survival. Factors responsible for this in-
teractionare not clearly understood.The
purpose of these studies was (1) to
assess theabilityof thedamto respondto
infectious-likeagents as pregnancy pro-
gresses and (2)to determineifhormones
thatchange in serum concentrationdur-
ingpregnancyaffectthis response.
Methods
We obtained lymphocy1es(the cells
mediating the immune response) from
blood samples of six heifers at monthly
intervalsthroughoutthe course of gesta-
tion. At the same sampling times, blood
samples were also obtained from six
ovariectomized(ovex) heifers as control
for seasonal effects. All heifers were
mixed breeds and were born the fall of
1978. The intact heifers were synchro-
nized and bred June 23 to 25, 1980.The
control heifers were ovariectomized in
April 1980.
The lymphocy1eswere assayed for
theirabilityto respondto twodifferentim-
munestimulants:ConcanavalinA (ConA)
and Pokeweed Mitogen (PWM). In some
studies,theresponsetotheseagentswas
determinedin thepresence and absence
(controls)of physiologicalconcentrations
of estrogen,estrone,andprogesterone.
Results
Table 1 summarizesthe immunere-
sponsiveness of lymphocy1esfrom preg-
nant heifers as a functionof gestational
stage, compared to responsiveness of
control lymphocy1esfrom ovex heifers.
Figure 1 demonstrates the inhibiting
effect of serum factors associated with
1Rita C. Manak is a research physiologist
atMARC.
22
--- ----
pregnancyon immuneresponsiveness of
lymphocytesobtainedfrompregnantheif-
ers. Together, these data suggest that
duringpregnancy,the potentialof the im-
mune response to recognize and over-
come infection is heightened. However,
superimposedon that $ituationis the ex-
istance of soluble substances in the
serum of pregnant animals, which can
further regulate responsiveness. Thus,
the immune response of pregnant ani-
mals appears to be under the control of
severalmechanisms.
To assess the role of soluble steroid
hormones, which increase in the serum
duringpregnancy,lymphocytesfrom200-
day pregnant and ovex heifers were
assayed in the presence of estrone,
estrogen, and progesterone. Figure 2
shows that progesterone,estrone, and to
a lesserextent,estrogen, are indeed cap-
able of depressing lymphocy1erespon-
siveness. Further work is in progress to
define these regulatorymechanisms and
its effectson the healthstatus of the dam
and her fetus.
Table 1.-Stage of pregnancyon
lymphocyter sponsiveness
Responseofpregnantheifers
Stageofgestation Responseofovexheifers
(%)
X 100
Prebreeding __
1st Trimester __
2nd Trimester
3rdTrimester_ _
80
130
160
190
COllA inducedresponseof pregnantheifer lymphocytes
_20
v
Q
x
[ 161" /
w
z
5 12
~
)0-
X
l-
I
X
".,
5 10
Figure 1.
-----
STEER ~
25
COllA(}'g/ml)
50
Effectof 0.5ng/mlsteroidlmlon PBL responseto ConA
100, AVGOF 6 OVEX HEIFERS AVG OF 5 200- DAY PREGriANT HEIFERS
-I
o
II:I-
t5
(,)
lL.o
"eo
PROG. ESTRONE ESTROGEN
Figure2.
-----
PROG. ESTRONE ESTROGEN
-- - --- ----


Effect of Pregnancy on Disease Resistance

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Roman L. Hruska U.S. Meat Animal Research Center U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska 1982 Effect of Pregnancy on Disease Resistance Rita C. Manak U.S. Meat Animal Research Center Follow this and additional works at: https://digitalcommons.unl.edu/hruskareports  Part of the Animal Sciences Commons Manak, Rita C., "Effect of Pregnancy on Disease Resistance" (1982). Roman L. Hruska U.S. Meat Animal Research Center. 9. https://digitalcommons.unl.edu/hruskareports/9 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Roman L. Hruska U.S. Meat Animal Research Center by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. RitaC.Manak1EFFECT OF PREGNANCY ON DISEASE RESISTANCESummaryDuring pregnancy, the immune re-sponseofcattlehasanalteredpotentialtoovercome infectionthan during an openperiod. Several mechanisms seem tocontrol this immune response, and theyare beingcurrentlyresearched.IntroductionDuring pregnancy,the dam's abilityto respondto bacteriaand viruses and toresist infection (its immune system) isalteredsomewhatto protectthedevelop-ingfetus.While thissystemmustcontinueto protect against infection, it must bemodulatedtoavoidrejectingthefetusas ifitwerea growingforeignorgantransplant.A disruptionof thisbalancehas impactondamandfetalhealthas wellas on embryosurvival. Factors responsible for this in-teractionare not clearly understood.Thepurpose of these studies was (1) toassess theabilityof thedamto respondtoinfectious-likeagents as pregnancy pro-gresses and (2)to determineifhormonesthatchange in serum concentrationdur-ingpregnancyaffectthis response.MethodsWe obtained lymphocy1es(the cellsmediating the immune response) fromblood samples of six heifers at monthlyintervalsthroughoutthe course of gesta-tion. At the same sampling times, bloodsamples were also obtained from sixovariectomized(ovex) heifers as controlfor seasonal effects. All heifers weremixed breeds and were born the fall of1978. The intact heifers were synchro-nized and bred June 23 to 25, 1980.Thecontrol heifers were ovariectomized inApril 1980.The lymphocy1eswere assayed fortheirabilityto respondto twodifferentim-munestimulants:ConcanavalinA (ConA)and Pokeweed Mitogen (PWM). In somestudies,theresponsetotheseagentswasdeterminedin thepresence and absence(controls)of physiologicalconcentrationsof estrogen,estrone,andprogesterone.ResultsTable 1 summarizesthe immunere-sponsiveness of lymphocy1esfrom preg-nant heifers as a functionof gestationalstage, compared to responsiveness ofcontrol lymphocy1esfrom ovex heifers.Figure 1 demonstrates the inhibitingeffect of serum factors associated with1Rita C. Manak is a research physiologistatMARC.22--- ----pregnancyon immuneresponsiveness oflymphocytesobtainedfrompregnantheif-ers. Together, these data suggest thatduringpregnancy,the potentialof the im-mune response to recognize and over-come infection is heightened. However,superimposedon that $ituationis the ex-istance of soluble substances in theserum of pregnant animals, which canfurther regulate responsiveness. Thus,the immune response of pregnant ani-mals appears to be under the control ofseveralmechanisms.To assess the role of soluble steroidhormones, which increase in the serumduringpregnancy,lymphocytesfrom200-day pregnant and ovex heifers wereassayed in the presence of estrone,estrogen, and progesterone. Figure 2shows that progesterone,estrone, and toa lesserextent,estrogen, are indeed cap-able of depressing lymphocy1erespon-siveness. Further work is in progress todefine these regulatorymechanisms andits effectson the healthstatus of the damand her fetus.Table 1.-Stage of pregnancyonlymphocyter sponsivenessResponseofpregnantheifersStageofgestation Responseofovexheifers(%)X 100Prebreeding __1st Trimester __2nd Trimester3rdTrimester_ _80130160190COllA inducedresponseof pregnantheifer lymphocytes_20vQx[ 161" /wz5 12~)0-Xl-IX".,5 10Figure 1.-----STEER ~25COllA(}'g/ml)50Effectof 0.5ng/mlsteroidlmlon PBL responseto ConA100, AVGOF 6 OVEX HEIFERS AVG OF 5 200- DAY PREGriANT HEIFERS-IoII:I-t5(,)lL.o"eoPROG. ESTRONE ESTROGENFigure2.-----PROG. ESTRONE ESTROGEN-- - --- ----

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Effect of Pregnancy on Disease Resistance

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