TY  - JOUR
T1  - Humoral Immune Response Assessment in Sheep Experimentally Infected with <I>Histophilus somni</I> and Previously Inoculated with Parainfluenza 3 Virus
AU - , Laura Garcia Celis AU - , Jehieli Girela alvarez AU - , Beatriz Arellano-Reynoso AU - , Victor Tenorio Gutierrez AU - , Francisco Aguilar Romero AU - , Pedro Mejia Sanchez AU - , Francisco Suarez-Guemes AU - , Efren Diaz-Aparicio 
JO  - Journal of Animal and Veterinary Advances
VL  - 6
IS  - 5
SP  - 681
EP  - 685
PY  - 2007
DA  - 2001/08/19
SN  - 1680-5593
DO  - javaa.2007.681.685
UR  - https://makhillpublications.co/view-article.php?doi=javaa.2007.681.685
KW  - Haemophilus somnus
KW  -Histophilus somni
KW  -immunoglobulin
KW  -sheep
KW  -inoculated
KW  -humoral immune response
AB  - There are no assays of experimental infection of sheep with <I>Histophilus somni</I> and their immune response. In order to know the humoral immune response of sheep experimentally infected by respiratory tract with <I>H. somni</I>, 19 male, 6 month-old sheep were immuno-suppressed with dexamethasone, 1 day before being inoculated with Parainfluenza 3 virus and during 5 days after viral inoculation. Seven days after viral inoculation, one animal was slaughtered in order to observe lesions caused by the virus. Another 12 animals were inoculated intratracheally with <I>H. somni</I> (1×10<SUP>9</SUP> UFC mL <SUP>1</SUP>), leaving 6 animals as controls that received same pathway sterile PSS. Heart and respiratory rates were taken, as well as rectal temperature, during 14 days after challenge. Serum and nasal exudate samples were collected to determine IgG, IgM and IgA levels by indirect ELISA test, using <I>H. somni</I> 40 kDa outer membrane protein as antigen. Two sheep from the inoculated group and one from the control group were humanely euthanized every week during 6 weeks. Samples were collected from lung, tonsils, retropharyngeal and mediastinal lymph nodes; bacteriology studies were carried out in duplicate and DNA was extracted to perform PCR with primers<I> </I>designed for<I> </I> 16S<I> </I> ribosomal  region<I> </I> in<I> H. somni</I>. Infected animals had temperature and respiratory rate increase, cough and mucopurulent nasal exudate; areas in the apical lung lobule were consolidated and there were adherences as well as. <I>H. somni</I> was isolated from only one animal from retropharyngeal node. Nevertheless, from nasal exudate samples, 11 of 12 infected sheep came out positive by PCR while the 6 non-infected controls were negative. ELISA test results for IgG were significantly different between infected and control animals at days 4 and 7 after inoculation, while no differences were found in IgM and IgA. It was concluded that in sheep experimentally infected, <I>H. somni</I> caused an IgG isotype humoral immune response. The presence of the bacteria could be detected by PCR in 91.66% of the animals. Even though the strain used in this research was previously passed through sheep, it did not cause lesions or signs that could suggest infection and it could not be recovered by bacteriology in most of the infected sheep.
ER  -