CD21 Lentiviral Activation Particles (h): sc-401352-LAC

CR2 encodes CD21 (complement receptor 2), a B cell–enriched surface receptor that binds C3d-tagged antigens and couples innate complement signals to adaptive humoral immunity. CD21 functions within the CD19–CD81 co-receptor complex to lower B cell activation thresholds, augment BCR signaling, and promote antigen capture and retention on follicular dendritic cells, shaping germinal center reactions. Through these roles, CR2/CD21 influences processes including complement-dependent opsonization, B cell maturation, and immunological memory formation. Dysregulated CR2 expression or signaling has been associated with altered B cell responses in autoimmune and infectious disease contexts and is frequently leveraged as a marker and functional node in B cell biology studies.

CD21 Lentiviral Activation Particles (h) address this need by packaging the complete synergistic activation mediator (SAM) transcriptional activation system into transduction-ready, high-titer lentiviral particles, enabling efficient CR2 upregulation across a broader range of human cell types.

CD21 Lentiviral Activation Particles (h) deliver all functional components of the synergistic activation mediator (SAM) system via lentiviral transduction. The system comprises three particle preparations co-transduced into target cells: one encoding catalytically inactive dCas9 (D10A and N863A mutations) fused to the VP64 transactivation domain with a blasticidin resistance gene; one encoding the MS2-p65-HSF1 fusion protein with a hygromycin resistance gene; and one encoding a target-specific 20 nt sgRNA fused to two MS2 RNA aptamers with a puromycin resistance gene. Following lentiviral transduction and genomic integration of the expression cassettes, the SAM components are stably expressed and assemble at the target locus within the proximal promoter region upstream of the CR2 transcriptional start site, where VP64, p65, and HSF1 act cooperatively to recruit endogenous transcriptional machinery and drive sustained upregulation of endogenous CD21 expression. The use of nuclease-inactive dCas9 avoids the introduction of double-strand DNA breaks and preserves the native CR2 genomic locus and regulatory architecture.

The lentiviral format offers several practical advantages: stable genomic integration supports heritable activation across cell divisions; high-titer particle preparations eliminate the need for in-house viral production; and compatibility with primary, non-dividing, and transfection-resistant cell types expands experimental accessibility. Successful transduction can be confirmed and enriched through triple antibiotic selection using puromycin, hygromycin, and blasticidin.

For Research Use Only. Not Intended for Diagnostic or Therapeutic Use.