This study evaluated the early modulation of the phenotype and cytokine secretion in swine immune cells treated with an engineered killer peptide (KP) based on an anti-idiotypic antibody functionally mimicking a yeast killer toxin. The influence of KP on specific immunity was investigated using porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) as ex vivo antigens. Peripheral blood mononuclear cells (PBMC) from healthy pigs were stimulated with KP and with a scramble peptide for 20 min, 1, 4 and 20 h or kept unstimulated. The cells were analyzed using flow cytometry and ELISA. The same time-periods were used for KP pre-incubation/co-incubation to determine the effect on virus-recalled interferon-gamma (IFN-γ) secreting cell (SC) frequencies and single cell IFN-γ productivity using ELISPOT.

KP induced an early dose-dependent shift to pro-inflammatory CD172α⁺CD14^+high monocytes and an increase of CD3⁺CD16⁺ natural killer (NK) T cells. KP triggered CD8α and CD8β expression on classical CD4⁻CD8αβ⁺ cytotoxic T lymphocytes (CTL) and double positive (DP) CD4⁺CD8α⁺ Th memory cells (CD4⁺CD8α^+low CD8β^+low). A fraction of DP cells also expressed high levels of CD8α. The two identified DP CD4⁺CD8α^+high CD8β^+low/+high CTL subsets were associated with tumor necrosis factor alpha (TNF-α) and IFN-γ secretion. KP markedly boosted the reactivity and cross-reactivity of PRRSV type-1- and PCV2b-specific IFN-γ SC. The results indicate the efficacy of KP in stimulating Th1-biased immunomodulation and support studies of KP as an immunomodulator or vaccine adjuvant.

这项研究评估了功能性模仿酵母杀手毒素的抗独特型抗体对工程化杀手肽（KP）处理的猪免疫细胞中表型和细胞因子分泌的早期调节。使用猪生殖和呼吸综合症病毒（PRRSV）和2型猪圆环病毒（PCV2）作为离体抗原，研究了KP对特异性免疫的影响。用KP和加扰肽刺激健康猪的外周血单个核细胞（PBMC）20分钟，1、4和20小时，或保持不受刺激状态。使用流式细胞仪和ELISA分析细胞。使用相同的时间段进行KP预孵育/共孵育，以使用ELISPOT确定对病毒召回的干扰素-γ（IFN-γ）分泌细胞（SC）频率和单细胞IFN-γ生产率的影响。

KP诱导早期剂量依赖性转变为促炎性CD172α ⁺ CD14 ^+高单核细胞，而CD3 ⁺ CD16 ⁺自然杀伤（NK）T细胞增加。KP触发经典CD4 ^- CD8αβ ⁺细胞毒性T淋巴细胞（CTL）和双阳性（DP）CD4 ⁺ CD8α ⁺ Th记忆细胞（CD4 ⁺ CD8α ^+低CD8β ^{+ low}）上的CD8α和CD8β表达。一部分DP细胞也表达高水平的CD8α。这两个确定的DP CD4 ⁺ CD8α ^+高CD8β ^{+低/ +高}CTL亚群与肿瘤坏死因子α（TNF-α）和IFN-γ分泌有关。KP显着提高了PRRSV 1型和PCV2b特异性IFN-γSC的反应性和交叉反应性。结果表明，KP可以刺激Th1偏向的免疫调节，并支持KP作为免疫调节剂或疫苗佐剂的研究。