Direct dual immunofluorescence of B. burgdorferi in the
gut of partially engorged (48 hr) ticks and in the mouse dermis.
(a and b) The same field double-labeled
with a FITC-conjugated polyclonal B. burgdorferi
antibody (a) and a TR-conjugated mAb against OspA
(b). (c and d) The same
field labeled with FITC-conjugated polyclonal Borrelia
antibody (c) and a TR-conjugated mAb against OspC
(d). (e) Merged image of spirochetes
stained with Alexa 488-conjugated OspA (green) and TR-conjugated OspC
(red). Three phenotypes were observed in e: arrows,
Borrelia producing only OspA in green, only OspC in red,
and both OspA and OspC in orange. (f) Mouse skin
sample attached to the hypostome of a tick that had fed for 40 hr is
labeled with the FITC-conjugated polyclonal Borrelia
antibody. The hypostome itself autofluoresces, and bacteria staining
with the antibody are indicated by the arrowhead. (Bars in a,
c, and e represent 20 μm, and the bar in
f represents 50 μm.)