Helper phage

A number of phagemid display systems that fuse Ab chains to either full-length or N-terminally deleted gp3 fusions have been described, along with the polymerase chain reaction (PCR) primer sets, restriction enzymes, and host strains required for the display of scFvs and Fabs (3—7). Some systems are commercially available. There is an important difference in whether the Ab-gp3 fusions are with the whole of the protein or with just the C-terminal domain. Fusions to the whole of gp3 require that the expression of the fusion is suppressed until after it is infected with the helper phage because of the resistance... 

VCSM13 (Stratagene) interference-resistant helper phage... 

Infect 200 pL E coli TG1 at OD = 02 with 10-pL serial dilutions of helper phage in order to obtain well-separated plaques. Add to 3 mL H-top agar (42°C), and pour onto warm TYE plates. Allow to set, and then incubate overnight. 

Infect the remaining 10 mL of culture with helper phage in a ratio of 20 1 (phage.bactena) (see Note 3). 

Figure 22.2 Cellular activation by CpG DNA. CpG DNA directly activates dendritic cells (DCs), monocytes and macrophages, to express increased levels of co-stimu-latory molecules, to increase antigen presentation, and to secrete high levels of chemokines and cytokines, such as interleukin 12 (IL-12), interferon-a(IFN-a), and tumor necrosis factor-a (TNF-a), and monocytes and macro-phages have increased antibody-dependent cellular cytotoxicity (ADCC) activity. NK cells are induced to express IFN-7 by these cytokines acting in concert with CpG, and have increased lytic activity. B cells rapidly produce IL-b and IL-10 and express increased levels of costimulatory molecules. B cells rapidly enter the cell cycle and become resistant to some forms of activation-induced cell death. T cells are not directly activated by CpG, but because of the T helper 1 (Thl)-like cytokine environment, and the increased antigen presenting cell (APC) activity, antigen-specific Thl cells and cytotoxic T lymphocytes (CTL) are generated.

Vector type Genotype Helper phage / hybrid protein copies per phage particle Typical vector(s) Reference(s)... 

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