The present invention refers to a fusion protein comprising a TNF-superfamily (TNFSF) cytokine or a receptor binding domain thereof fused to a collectin trimerization domain, to a nucleic acid molecule encoding the fusion protein, and to a cell comprising the nucleic acid molecule. The fusion protein is present as a trimeric complex or as an oligomer thereof. The fusion protein, the nucleic acid, and the cell is suitable as pharmaceutical composition or for therapeutic, diagnostic and/or research applications.