Note:
air-dried resin sections can be stored for months prior to labelling.

• Encircle sections with a water repellent silicon pen (e.g. PAP-Pen from Electron Microscopy Sciences, Ft. Washington, PA or Sciences Services, Munich).
• Incubate sections with blocking buffer, e.g. PBG (0.2 % gelatin, 0.5 % BSA in PBS or TRIS) or 1% milk powder in PBS for 10 min.
• Remove blocking buffer, add 25 µl of the primary antibody solution per coverslip (with a final concentration in the range of 1-5 µg specific IgG/ml) and incubate for 30 -60 min.
• Wash 5 times with buffer and incubate with fluorochrome-labelled second antibodies, similar to the primary antibody staining conditions. s Wash 5 times with buffer and counterstain nuclei with DAPI, Hoechst dye or propidium iodide (0.4-0.1 µg/ml in H2O) for 5 min.
• After a final wash with buffer mount coverslips on glass slides using a small drop of mounting medium (like Elvanol or Moviol 4.88) for semipermanent embedding. The addition of anti-fading agents like DABCO (25-100 mg/ml), Paraphenylenediamine (1 mg/ml) or n-propyl gallate (10 mg/ml) is strongly recommended.
• Use oil immersion objectives to examine.
  CAVEAT: All solutions should be centrifuged before use for 2 min. at 10,000 rpm. Avoid air-drying during all incubation steps.

References:

Immunofluorescence on ultrathin resin sections:

• Albrecht U, Seulberger H, Schwarz H, and Risau W. (1990) Brain Res.535, 49-61.
• Schwarz H, Hohenberg H, and Humbel BM. (1993) Immuno-Gold Electron Microscopy in Virus Diagnosis and Research (CRC Press, Boca Raton), pp 349-376.
• Schwarz H, Müller-Schmid A, and Hoffmann W. (1993) Cell Tissue Res. 273, 417-425.
• Schwarz H. (1994) Electron Microscopy 1994 ICEM 13-Paris (Jouffrey B, and Colliex C, eds.), Les Editions de Physique, Les Ulis, France, Vol. 3, 255-256.
• Fialka I, Schwarz H, Reichmann E, Busslinger M, and Beug H. (1996) J. Cell Biol. 132, 1115-1132.
• Kurth T, Schwarz H, Schneider S, and Hausen P. (1996) Cell Tissue Res. 286, 1-12.

Semi-permanent mounting medium containing polyvinylalcohols (Elvanol/Moviol):

• Rodriguez J, and Deinhardt F. (1960) Virology 12, 316.
• Lennette OA. (1978) Am. J. Clin. Path. 69, 647-648.

Antifading agents:

1,4-Diazobicyclooctane (DABCO):

Johnson GD et al, 1982. J. Immunol. Meth. 55, 231-242.
Langanger G, De Mey J, and Adam H. (1983) Mikroskopie 40, 237-241.

Paraphenylendiamine:

Johnson GD, and Araujo GMDCN. (1981) J. Immunol. Meth. 43, 349-350.

n-Propyl gallate:

Giloh H, and Sedat JW. (1982) Science 217, 1252-1255.