Different approaches for obtaining antibodies from human B cells.

Antibodies have emerged as powerful therapeutics effective for treating a number of human conditions and diseases. While early successes utilized small animals to generate therapeutic antibodies, human antibodies are now preferred in order to limit anti-antibody immune responses. Antibodies with human amino acid sequences can be generated in a number of ways, such as humanizing antibodies from other species or expressing human antibodies in transgenic animals.

Specific inhibition of the classical complement pathway with an engineered single-chain Fv to C1q globular heads decreases complement activation by apoptotic cells.

Apoptotic cells are potent complement activators; and proposed mechanisms include IgM-mediated classical pathway activation, C-reactive protein (CRP)-mediated classical pathway activation, and IgM-mediated lectin pathway activation. While complement activation is beneficial in clearing apoptotic cells, the resulting complement-mediated inflammation may extend damage to the surrounding cells and tissues, as observed in ischemia/reperfusion injury. We previously engineered and characterized a single-chain Fv against C1q globular heads (scFv(QuVHVL)) that blocked C1q binding to immobilized IgG and to IgG-sensitized cells, and thereby inhibited IgG-mediated classical pathway activation [Hwang H.

Back-burning to cure HIV: temporary depletion of all CD4+ cells and elimination of the extracellular reservoir with HIV immunotoxin therapy.

Temporary elimination of all host cells for the human immunodeficiency virus (HIV) combined with dislodging HIV from its extracellular reservoir could cure acquired immunodeficiency syndrome (AIDS). This combination would be effective because the virus is dependent on host cell integration or on the membrane protection of B cells or of follicular dendritic cells (FDCs) for its survival and because the CD4(+) host cells are leukocytes that are naturally renewable through hematopoiesis. By treating HIV patients with a combination of humanized antibodies it should be possible to achieve both goals.

Highly specific inhibition of C1q globular-head binding to human IgG: a novel approach to control and regulate the classical complement pathway using an engineered single chain antibody variable fragment.

We sought to specifically regulate the binding of human C1q, and thus the activation of the first complement component, via the construction of a single chain antibody variable binding region fragment (scFv) targeting the C1q globular heads. Here we describe details of the construction, expression and evaluation of this scFv, which was derived from a high-affinity hybridoma (Qu) specific for the C1q globular heads. The scFv was comprised of the Qu variable heavy chain domain (VH) linked to the Qu variable light chain domain (VL) and was termed scFv-QuVHVL.