In real life, people use facial expressions, bodily gestures, and tone variations to convey information more clearly and dramatically. Such multimodal communication is effective, but also requires significant mental and physical efforts on the part of the communicator. In virtual reality (VR), such efforts can be much relieved not only automatically but also in a much more amplified way, which would not possible in real life. In this paper, we investigate the effects of exaggeration and highlighting of gestures when communicating in VR. The exaggeration and highlighting method we consider is enlarging and exaggerating of the gestural body parts. We conduct a comparative experiment in which a VR user tries to understand an avatar conveying a short passage or describing a concept word only in gestures with the avatar's gesturing body parts appropriately enlarged (or not). Our experiment has shown that there was not only the expected communication efficacy depending on the type of content to be conveyed, there was also a significant influence to the level of concentration, immersion and even presence.