| Abstract: | The applicability of the recombinant LipL32 for serodiagnosis of leptospiral infection in field rodents was
assessed in this study. An immunodominant region of LipL32 was determined by monoclonal antibodies, and then,
truncated LipL32 (tLipL32) was designed to contain the region (87–188th amino acid). The tLipL32 was compared
between two recombinant expression hosts Escherichia coli and Pichia
pastoris in ELISA. With field rat sera, tLipL32 expressed by P. pastoris
(tLipL32p) had high antigenicity without background reactions, while tLipL32 expressed by E.
coli (tLipL32e) showed high background reactions, which were reduced by pre-adsorption of sera with
E. coli. To evaluate tLipL32-ELISA, field rat sera were tentatively divided into a
Leptospira infection positive (12 sera) and a negative group (12 sera) based on the results
from flaB gene PCR of kidney samples and WB with whole Leptospira cell.
Consequently, the sensitivity of tLipL32p-ELISA for field rat sera was 83% . A similar result was obtained
from tLipL32e-ELISA with adsorbed sera, (92%). However, sensitivity of tLipL32e-ELISA using sera without an
adsorption treatment was 50%. Regardless of the expression host, tLipL32-ELISA had 100% specificity and
sensitivity in experimentally infected laboratory rats. These results suggest that recombinant LipL32
expressed by P. pastoris is more applicable for serodiagnosis in field rats due to a lack of
background reaction. |
