fa Original article Original article <div style="text-align: justify;"><strong>Introduction:</strong> Due to the role of neutralizing antibodies which can prevent human cytomegalovirus (HCMV) infection, most of the efforts have been focused on&nbsp; designing vaccines capable of eliciting protective humoral immunity. The aim of this study was to evaluate the antibody response of BALB/c mice to a truncated HCMV glycoprotein B produced in insect cells using Baculovirus Expression Vector System (BEVS). <strong>Methods: </strong>The ectodomain of HCMV gB coding sequence was synthesized and the recombinant protein was expressed in <em>Spodoptera frugipedra</em> (Sf9) insect cell line using BEVS. The expression of the recombinant HCMV gB was verified using an HRP-conjugated polyclonal antibody, specific for HCMV gB. The levels of antibody responses and characterization of the subclasses of IgG antibodies were evaluated after vaccination of the mice. <strong>R</strong><strong>esults:</strong> The expression of truncated HCMV gB protein (~ 70 kDa) in the infected insect cells was verified by Western blot analysis. Measurement of IgG subclasses showed the dominance of IgG1 subclass response among all of the IgG subclasses (<em>P</em> < 0.05) while the titers of IgG2a and IgG2b were approximately the same. <strong>Conclusion: </strong>This study demonstrated that BEVS could be used as an efficient approach for the expression of this truncated protein. The results also showed the use of this recombinant protein as a subunit vaccine could induce a significant antibody response, tilted toward IgG1.</div> Human cytomegalovirus, Ectodomain of glycoprotein B, Subunit vaccine. 41 45 http://vacres.pasteur.ac.ir/browse.php?a_code=A-10-1-40&slc_lang=fa&sid=1 A Azizi Saraji No Department of Virology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. S Asiyabi No Bam University of Medical Sciences, Bam, Iran. F Jalali No Bam University of Medical Sciences, Bam, Iran. MR Aghasadeghi No Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran. M Shahmehri No Department of Medical Lab Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran. R Vahabpour Yes Department of Medical Lab Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.